Running rough

Hi all. My 95 SC has been running really rough, between 30 and 60 mph. When it does it at highway speed, the best way to describe it is surging, almost like tranny is going back and forth in OD, but its not the tranny, I know that. sometime you step on the gas and it hesitates and stutters. It sometimes idles real rough. The check engine light has come on twice, but went out after next start of the engine. Sometimes is runs fine. And sometimes manuvering through parking lot it just dies, It does start right back up though. Heat seems to agrivate the issue. Im thinking plugs, wires, new filter (fuel and air) and remove the TB and clean. Does this sound right. I have read a lot of threads here and this is what I came up with. Can anyone guide me to a thread to describe removing the TB, and/or changing the fuel filter. I did a search for them but obviously arent using the right keywords. I was going to see if the code was still in the computer, but those ripoff artists at pep boys wanted 100 bucks just to hook the car to the computer and get the codes, and Im not even sure they exist since the light has stopped coming on. Thanks for any input guys.

I think it's the ignition wires. Could do the plugs while you're in there, but you don't absolutely need to. The wires alone will probably fix your problem.

AA wrote:

I think it's the ignition wires. Could do the plugs while you're in there, but you don't absolutely need to. The wires alone will probably fix your problem.

Thanks I was planning to do the wires and fuel and air filters first, maybe tommorow since I am off work.

Also, pick up a can of MAF Sensor or Electrical/Electronics cleaner and start out with just cleaning your Mass Air Flow sensor, rather than pulling the whole TB... Read this page all the way to the bottom:

https://rivperformance.editboard.com/series-i-engine-transmission-f13/mass-air-flow-t2149.htm?highlight=mass


[[ Does anyone know for sure if the Series I used the stupid security Torx screws on the MAF sensor, like the Series II? ]]

TheAviator wrote:

Hi all. My 95 SC has been running really rough, between 30 and 60 mph. When it does it at highway speed, the best way to describe it is surging, almost like tranny is going back and forth in OD, but its not the tranny, I know that. sometime you step on the gas and it hesitates and stutters. It sometimes idles real rough. The check engine light has come on twice, but went out after next start of the engine. Sometimes is runs fine. And sometimes manuvering through parking lot it just dies, It does start right back up though. Heat seems to agrivate the issue. Im thinking plugs, wires, new filter (fuel and air) and remove the TB and clean. Does this sound right. I have read a lot of threads here and this is what I came up with. Can anyone guide me to a thread to describe removing the TB, and/or changing the fuel filter. I did a search for them but obviously arent using the right keywords. I was going to see if the code was still in the computer, but those ripoff artists at pep boys wanted 100 bucks just to hook the car to the computer and get the codes, and Im not even sure they exist since the light has stopped coming on. Thanks for any input guys.

You mention that the CEL has come on and gone off a couple of times, May I suggest you read those codes first before replacing any parts. Go somewhere other than pep boys for a $100.00. You can go to a GM dealer and you'll be sure that they can read the codes for a 1995 and they may not charge you anything or they may have a minimum $$$ policy. But at least they have the most accurate equipment. If your going to pay someone over $100 to read codes then you can buy the code reader on Amazon for $129.00 that works for the 95 and other years. It is Actron model CP9145.
The codes will lead you down the right path.
Even if the CEL is off, the codes will be stored in memory if it hasn't been too long since the light came on last.

Mark to answer your question, no the series 1 does not use the torx screws. It has three phillips screws holding it in.

Rickw wrote:

You mention that the CEL has come on and gone off a couple of times, May I suggest you read those codes first before replacing any parts. Go somewhere other than pep boys for a $100.00. You can go to a GM dealer and you'll be sure that they can read the codes for a 1995 and they may not charge you anything or they may have a minimum $$$ policy. But at least they have the most accurate equipment. If your going to pay someone over $100 to read codes then you can buy the code reader on Amazon for $129.00 that works for the 95 and other years. It is Actron model CP9145.
The codes will lead you down the right path.
Even if the CEL is off, the codes will be stored in memory if it hasn't been too long since the light came on last.

O'Reilly or Autozone will read the codes for free. I know at my shop, the checkout fee for a SES light is around $90. However, for that $90 I read the code(s), and find the EXACT problem from there. Whether it takes me 2 hours or 5 minutes, I find the problem. Codes do nothing but point you in the right direction, as Rick said. If they told you $100 to "read the codes", they probably meant a complete diagnosis......

Its possible that Pepboys meant a complete diagnostic scan but I wouldnt let Pepboys TOUCH my car, and I certinally wouldn't pay them $100 to do it. It may be different where you're from, but in Jersey Pepboys is known for doing hackwork. Most of their employees are still in highschool and are not certified. I had a friend who went for an oil change and they forgot to put the drain plug back in and BOOM. They've sold me enough crappy parts that I've learned my lesson. Just my 2 cents, like I said it may be different in different areas.

Derek wrote:

Mark to answer your question, no the series 1 does not use the torx screws. It has three phillips screws holding it in.

Thanks, that's one headache he doesn't need...

Derek wrote:

Its possible that Pepboys meant a complete diagnostic scan but I wouldnt let Pepboys TOUCH my car, and I certinally wouldn't pay them $100 to do it. It may be different where you're from, but in Jersey Pepboys is known for doing hackwork. Most of their employees are still in highschool and are not certified. I had a friend who went for an oil change and they forgot to put the drain plug back in and BOOM. They've sold me enough crappy parts that I've learned my lesson. Just my 2 cents, like I said it may be different in different areas.

Believe me, it's not much different 'round here either. Just justifying the charge, that's all. And no, PepBoys wouldn't even get the chance to see my car in the parking lot......in fact, no shop will ever touch my car (except exhaust). I'm a mechanic and have the means of repairing myself

Abaddon wrote:

Believe me, it's not much different 'round here either. Just justifying the charge, that's all. And no, PepBoys wouldn't even get the chance to see my car in the parking lot......

Tell me about it!
After a lifetime of never having anyone outside the family touch my cars (or at least family friends,) I'm going to be paranoid as hell trying to choose a shop when I move out of state.

Hmmm. Maybe instead of buying a house with a 3 car garage, I should buy a shop with a 3 bedroom office...

Eldo wrote:

Hmmm. Maybe instead of buying a house with a 3 car garage, I should buy a shop with a 3 bedroom office...

Need a roommate?

I would start with plugs and wires as they are good maintenance items and could be very related to your problem. Beyond that, get your codes read and don't throw parts at it randomly.

Abaddon wrote:

Eldo wrote:

Hmmm. Maybe instead of buying a house with a 3 car garage, I should buy a shop with a 3 bedroom office...

Need a roommate?

Eldo wrote:

Hmmm. Maybe instead of buying a house with a 3 car garage, I should buy a shop with a 3 bedroom office...

Well, just an update, I have cleaned the MAF, replaced plugs, wires, and upstream o2 sensor. I have tested all three coil paks, with 6.2,6.3,6.2 K ohms respectavely. None of this has helped, any other ideas guys, I am scratching my head. Its like the car just starts jumping about 4-500 rpm randomly at lo throttle, around 45 mph, or under light accelaration. Heavy acceleration yields a slight hesitation (the SC I assume) and then a nice easy pull up to speed, no problem. Somtimes it idles rough, I am very confused and tearing my hair out. HELP....lol

TheAviator wrote:

Well, just an update, I have cleaned the MAF, replaced plugs, wires, and upstream o2 sensor. I have tested all three coil paks, with 6.2,6.3,6.2 K ohms respectavely. None of this has helped, any other ideas guys, I am scratching my head. Its like the car just starts jumping about 4-500 rpm randomly at lo throttle, around 45 mph, or under light accelaration. Heavy acceleration yields a slight hesitation (the SC I assume) and then a nice easy pull up to speed, no problem. Somtimes it idles rough, I am very confused and tearing my hair out. HELP....lol

OK, #1, what do you mean by cleaning the upstream O2 sensor, What did you actually do to it.
Did you remove and attempt to clean it, or are you assuming it got cleaned by spraying the throttle body and MAF.????

#2, Tested all coil packs, did you test primary or secondary windings to get an average of 6200 ohms or is 62,000 ohms, I'm sorry I'm a bit confused. The numbers don't look right, but could be depending on what you checked.

#3, Let me clarify, During normal acceleration the engine starts (jumping), doing something, that causes it to fluctuate 400 to 500 RPM, randomly (not all the time) during Low to cruising throttle setting.?

#4, Heavy acceleration yields a hesitation. Then a steady pull up to highway speeds.?

#5, Sometimes it idles rough.

Remember everyone who reads this, His car has extremely low miles.
Approximately 45,000 miles. But it is a 95. So it's 15 years old.

How many if any vacuum lines have been changed, especially the one going to the trans.? I read thru the whole thread and don't remember seeing a mention of ALL vacuum lines being changed. The one going to the Transmission modulator especially, unless that was a different post and I missed it.

Rick

Rickw wrote:

TheAviator wrote:

Well, just an update, I have cleaned the MAF, replaced plugs, wires, and upstream o2 sensor. I have tested all three coil paks, with 6.2,6.3,6.2 K ohms respectavely. None of this has helped, any other ideas guys, I am scratching my head. Its like the car just starts jumping about 4-500 rpm randomly at lo throttle, around 45 mph, or under light accelaration. Heavy acceleration yields a slight hesitation (the SC I assume) and then a nice easy pull up to speed, no problem. Somtimes it idles rough, I am very confused and tearing my hair out. HELP....lol

OK, #1, what do you mean by cleaning the upstream O2 sensor, What did you actually do to it.
Did you remove and attempt to clean it, or are you assuming it got cleaned by spraying the throttle body and MAF.????

#2, Tested all coil packs, did you test primary or secondary windings to get an average of 6200 ohms or is 62,000 ohms, I'm sorry I'm a bit confused. The numbers don't look right, but could be depending on what you checked.

#3, Let me clarify, During normal acceleration the engine starts (jumping), doing something, that causes it to fluctuate 400 to 500 RPM, randomly (not all the time) during Low to cruising throttle setting.?

#4, Heavy acceleration yields a hesitation. Then a steady pull up to highway speeds.?

#5, Sometimes it idles rough.

Remember everyone who reads this, His car has extremely low miles.
Approximately 45,000 miles. But it is a 95. So it's 15 years old.

How many if any vacuum lines have been changed, especially the one going to the trans.? I read thru the whole thread and don't remember seeing a mention of ALL vacuum lines being changed. The one going to the Transmission modulator especially, unless that was a different post and I missed it.

#1 I replaced the upstream o2 sensor
#2 on each coil pak, I removed both wires, attached a multi tester, and yeilded an average of 6300 ohms across the coil, did I do it wrong???
#3 Yes
#4 Yes
#5 Yes

No vacuum lines have been replaced, I wouldnt know where to look, but I hear no sucking sounds under throttle...

Thanks for any advice

You don't need to hear sucking sounds under acceleration to have multiple or even a single vacuum leak.

All the rubber vacuum hoses on your car should be replaced due to age, not mileage, especially the one going to your Transmission Modulator.

The cost of the rubber hoses is less than $10.00 to do them all.

If your not familiar or comfortable checking and changing them out, definitely pay someone to do it.

That would be my first course of action based on some of your squawks.

Going thru the vacuum system is a very good idea on a 15-year-old car, especially since the '95 has more hoses than any other year.

On another recent thread, where all sorts of theories were examined, a member just found that he has multiple vacuum leaks around his supercharger gasket and even the PCV valve cover...

Also, consider pulling/cleaning the throttle body, no spray-in will get the backside clean.

Albertj

Well I have now replaced all teh vacuum hoses and it still hasnt fixed the problem, although the hoses were really bad, I am shocked they held on as they did, They crumbled in my fingers as I went to remove them. I am to the point of thinking I have an ignition problem, so I guess, I will break down and spend the money on coils, although they all test out at around 6300 ohms, with a meter. Anyone else have any ideas. For those who havnt seen it, the car is stuttering under acceleration, its a 4-500 RPM stutter, like its misfiring bad, but I dont always have a SES light. Could it be Cam or crank position senor, TPS, EGR or PCM???Confusion abounds...lol

I would not replace anyting else until I pulled codes. Might be some old codes, if any, would give a cluse as to the running issues.

You say you do not have an SES lit. Well... if you have had one lit thre should be stored codes, Those codes will give us a badly needed hint as to the problem

If your vac hoses were that bad I would not be surprised to find a wiring problme - that is, an intermittent break in the harness at the firewall connector or at the coil pack.

First - please pull the (stored) codes and post.

Albertj

albertj wrote:

I would not replace anyting else until I pulled codes. Might be some old codes, if any, would give a cluse as to the running issues.

You say you do not have an SES lit. Well... if you have had one lit thre should be stored codes, Those codes will give us a badly needed hint as to the problem

If your vac hoses were that bad I would not be surprised to find a wiring problme - that is, an intermittent break in the harness at the firewall connector or at the coil pack.

First - please pull the (stored) codes and post.

Albertj

I have been to Pep boys, and Auto zone and no one has a scanner to pull the codes from OBD1, a friend tried his OBD1 scanner, but it doesnt work on rivieras with the climate control computer, at least that is what it says in his book. the scanner said couldnt comunicate with the car. I am going to break down and pay a mechanic to pull em, after all its only money.....sigh

TheAviator wrote:

albertj wrote:

I would not replace anyting else until I pulled codes. Might be some old codes, if any, would give a cluse as to the running issues.

You say you do not have an SES lit. Well... if you have had one lit there should be stored codes, Those codes will give us a badly needed hint as to the problem

If your vac hoses were that bad I would not be surprised to find a wiring problme - that is, an intermittent break in the harness at the firewall connector or at the coil pack.

First - please pull the (stored) codes and post.

Albertj

I have been to Pep boys, and Auto zone and no one has a scanner to pull the codes from OBD1, a friend tried his OBD1 scanner, but it doesnt work on rivieras with the climate control computer, at least that is what it says in his book. the scanner said couldnt comunicate with the car. I am going to break down and pay a mechanic to pull em, after all its only money.....sigh

1) you just need an OBD I scanner with the OBD II connector attached. I posted something about this in another thread, don't recall which ATM.

2) As for the erratic stuff, I wonder if maybe you have a bad alternator. Do your headlights pulsate at idle or at say 1000 or 2000 RPM? You could have a voltage regulator loose or gone bad which will cause all kinds of BS and nonspecific problems -- affects every sensor and such. If your headlights pulsate at idle you might want to go to a pick n pull and snag yourself a good (most in the junkyard will be good) alternator. Swap it in, watch many if not all the problems go away.


Albertj