Stuttering sometimes when driving

NGK Platinum G-Power TR55GP 3403 spark plugs. Exact enough for ya?

Well, we went up to the store awhile ago and it's still doing it the same. It seems more sporadic when it occurs but it's still happening. We tried some stuff to remove water in the fuel (That old nasty Shell V-Power might have had some in it). Still doing it. Hoping maybe with time and the other three spark plugs this will solve it, however it's looking less hopeful. If those don't fix it we'll go for the fuel filter. Otherwise, I'm thinking I may have to just take it and get it analyzed.

The oddest thing is that it only happens sometimes under moderate acceleration and under light acceleration in overdrive. It's ever so inconsistent to where it's not something you could easily attribute to something being bad. Any other ideas?

dirty MAF?
maybe even early symptoms of crank sensor failing. do you notice it happening only when the car is warmed up or does it stumble when cold too?

are you getting any SES?

I guess it could be the MAF being dirty, but I would think that would be happening especially under hard acceleration and it doesn't. The car does it cold or warm the same way - we drove around all over today and it was doing it warmed up and it does it when I'm on my way to school and it's cold.

No Service engine light, wish I did so there was something I could get scanned or checked out. As it is, I have no idea what else would be a likely culprit.

Who said changing spark plugs on our cars was easier? Because they're sorely mistaken. I looked at the GTP after we finished today - it looks so much easier and my dad said he rocked the motor up out of the dogbones to get to them easier and had lots of room.

the farthest to the passenger side spark plug wasn't too bad and the middle one was okay (Except the wire tore on it, another bad one we had to replace). The farthest to the driver side, now that was a PITA!!! Fought with it for what seemed like an eternity with both of us trying our best to get it off. We couldn't hardly reach down in there to get it. When we got it out, it was a different style of spark plug than the rest. The rest were all Autolite Platinums - it was a Bosch Platinum with two prongs on the tip. Hopefully now an entire matching set of six spark plugs will do the trick and the two wires that went bad that we replaced will help.

I hope it does, I have the sharpest pain in my ribs from leaning on the edge of the Riv while sticking my arm behind the motor. I scrubbed my hands and I'm still covered in oil and grime. My damn motor is slimy and nasty down there although I suppose it would be with this many miles. Oh how I wish we had a standard mounted V6 or an inline motor. Night and day difference I could imagine. I can only imagine how easy it must be on a four, five or six cylinder inline motor. A piece of cake compared to this.

Next time, we're taking it to someone to get those back plugs changed - or at least that driver side on in the back. Biggest PITA to reach. The car seemed to idle a little higher when I started it. Idled around 1100 rpm and even after putting in gear it didn't drop as much as normal. I'm not getting the 700 rpm I usually could get. Hoping after driving it tomorrow it will smooth out the bumps. Did have to unplug the O2 sensor before the DP because the wire was in the way and broke the stupid plastic piece holding it to the metal bracket doing it but we plugged it back in.

You people who live for this, I think you're crazy. I love cars but all the wires and electronics in the way and all the complications you can cause are ridiculous!

I can change out the 3 back plugs in under 10 mins - I've timed myself (no need to rock the engine forward with a Riv, what a waste of time). I don't find that very inconvenient to do once every 20-30k miles. And at a cost of $9 per set, that's less than 1/1000 of one penny per mile. That's called easy, cheap, reliable performance in my book.

When you swapped your dad's ignition wires, did you swap them all, or just the one you thought was bad? How old are his wires, and what kind are they?

Your engine could be idling higher because it's colder weather now. See how it does after driving for 15 mins.

Quote :

Did have to unplug the O2 sensor before the DP because the wire was in the way and broke the stupid plastic piece holding it to the metal bracket doing it but we plugged it back in.

WTF? did you break the wire, too? Make sure everything is still intact. I don't see why you would need to remove this to change spark plugs.

Quote :

You people who live for this, I think you're crazy.

I live for this because my Riviera is paid off and I think maintenance is the key reason why the car is running near perfect after 169k miles. I live for this because my friends who work on VWs and Hondas are jealous of me because my car is WAY easier to work on than theirs. I live for this because parts are easy to find and inexpensive, and this car is SO easy to modify. I live for this because guys in V-8 pony cars are impressed with how quick my Buick is. I could go on and on...

And I am a little crazy, but that has nothing to do with the car.

I disconnected the wiring up top. I couldn't stick my hand down to reach the spark plug with it in the way, I didn't take out the actual sensor.

The wires we swapped weren't too old since he replaced them not too long before the GTP started running bad. This last time he bought yet another set of new wires to see if that would fix the problem and put all of those on and all the new spark plugs (Which did fix the problem short term). My old probably original wires did tear on a few when I took them off, as I said 2 of 6 did.

In hindsight, yes replacing all of them would've been the smart thing to do but it was enough work doing all that other BS and all the other wires were fine. Maybe one day when I have too much money and feel like torturing myself I'll go out there and buy some new spark plug wires from MSD or something and get some bright colored ones.

And I'm going to call BS, unless you've removed some serious pieces under your hood or the '97+ are different than the '96 there's no way that last spark plug is an easy task.

I'm going to borrow this pic from mrod7510 to show what I am talking about:


Please do tell how you are able to reach that last spark plug oh so easily.

i reach it exactly as you have it pictures. i can fit my arm back there with plenty of room to remove the wire, take out the plug, and install the new one in a mater of minutes. no moving the engine forward, no removing the STB (like on regals), no cramped space between the firewall and block.
and if you have big arms then do it from below the car while it is on ramps. just as easy, and you can see what you are doing.

you just need to man up, get a little dirty, and do it.

From the passenger side, using a swivel ratchet with universal adapter and deep well socket, use your left arm to get behind the engine. Use a spot light to see the tip of the plug, or feel for it with your fingers.

I'm asking about the wires because what you are describing sounds exactly like bad wires. You can't tell the wires are bad by inspecting them, and you can't replace them with just any old V-6 wire set. My wires went bad around 109k miles, and they still looked brand new. I never did find out which one was bad.

When you say the car shudders at random times, I don't think it's so random, I think it's when you go into boost. This is when the PCM kicks the hotter spark tables, upping the ignition voltage. If your wires are old, they may not handle the current, or they may short through a tiny crack in the insulation.

I would take a very long wire off of your Dad's car and swap it to each cylinder until the problem goes away. It could be two bad wires, but usually they go one at a time. The earlier you try this, the better your chances of diagnosing the problem

Trust me, I got dirty from it. I have little red spots all over my arm where apparently my skin didn't like something under there, not to mention scratches all over my arms. I could reach the wire but just barely, it was wedged on very tightly and no matter how hard I yanked I couldn't get it to come loose. Maybe if you did it frequently they wouldn't get so stuck but the fact there was oil on that metal cover on the spark plug wire end piece didn't make it any easier to grab.

Are you all approaching from the passenger side or sitting in the engine bay facing the back of the car sticking your arm in and to the right? I was standing beside the car leaning over to get to it and that's why my ribs are sore. The wire I could've eventually yanked off but the ratchet was a total PITA. We had an extender on it and a deepwall but there was no room in there to turn it and no good way to torque on it and break it loose. Luckily my dad got it, I about killed myself trying to break it loose.

I still haven't driven it to see if it's resolved yet so I'll report back what it does when I drive it. It'd be really nice if it was fixed, I'm tired of that nasty feeling!

Shintsu wrote:

Who said changing spark plugs on our cars was easier?.

You did:

Shintsu wrote:

he rocked the motor up out of the dogbones to get to them easier

That makes it an easy job? We don't need to disconnect dogbones to rock the motor anywhere, you can without disconnecting anything if you must. What makes it easy is that you don't need to rock the motor at all: you just reach down below the alternator and across, simple, done.

Agree, even if you drive the car up on ramps and get underneath, that's easier than disconnecting mounts and rocking the engine forward.

I tried three times to make it do it today and I couldn't make it. Definately idling higher. It used to drop to 700 rpm before now it's 1100 rpm. What is the lowest your Riv's idle?

About 1100 RPM when the engine is cold and it's under 60ºF.

It's actually idling back down where it was before. It's been in the mid-40s all day and it definately won't drop below 1100 RPM when I've just started it. It does seem a bit rough when accelerating slightly in overdrive. It's not stuttering but it still feels a little rough - just normal with age or is that actually something else?

In cooler weather, 1100 RPM is normal until the car warms up. Accelerating slightly in OD means your TCC is locked up. Doing this creates a high torque demand, so the car will usually shake a little, especially if it is old and the engine mounts are soft. It's not a warning flag, but it can be eliminated with tuning. Or, you can alter your driving style to compensate. Try letting your foot off the gas right before you accelerate in OD.

Well, I don't have a tuner so unless you're referring to a different kind of tuning I don't suppose I have any way of tuning it so I'll just compensate for it.

Thanks for all the help everyone, I really appreciate it!

You're quite welcome!

AA, he has a 96 so trans tuning options are less.

Kevin, you can get a shift pressure modulator for $15 and it will make shifts feel more exact, faster and a little bit firmer. you can adjust the pressure with a screw driver.

Mr.Riviera wrote:

Kevin, you can get a shift pressure modulator for $15 and it will make shifts feel more exact, faster and a little bit firmer. you can adjust the pressure with a screw driver.

Carried by Advance Auto/Pep Boys? How and where does it go on?

Most of my problem doesn't come from shifts (Which are very firm as is), it's just the motor sort of makes the car vibrate a little more than normal when I give it the gas in OD. If I give it enough to downshift into 3rd it's fine, it's just that acceleration in OD that does it.

https://rivperformance.editboard.com/series-ii-engine-transmission-f4/shift-modulator-t2515.htm?highlight=shift+modulator

i think what you are describing is normal for our motors/tranny's.
just thought you should know about the 96 tranny mod since it is specific to 96's.

I realize options are less for tuning a '96, but since the TCC clutch is still controlled electronically, I thought you would have the option to change the lock-up behavior. Maybe?

Shintsu wrote:

[it's just the motor sort of makes the car vibrate a little more than normal when I give it the gas in OD. If I give it enough to downshift into 3rd it's fine, it's just that acceleration in OD that does it.

I think what you are describing is normal. Want smoother low end torque... add more cylinders... The 455 does a nice job of this!

Ahh, it would also do a better job at drinking the gas too! I suppose this is as good a place as any to say this brief story.

Some clown on Youtube doing a weak burnout in a four cyl Honda Accord and I said it was weak as hell. Then some commenter says something like "lol, you drive a buick that's shit! you should get a good car like a tuner! hah a fukc buiks! Honda 4 life!" or something like that (Poor grammar, misspellings, the whole lot of it).

Yes, I should trade this nice Riviera for a Honda. It was once a consideration for me but little asses like this really bring out the muscle side of me. Heh, I'd love to have an old Rivie now with gas the way it is. Be able to do something like this that a Honda could never do due to a certain lack of TORQUE!


This is also badassery

Bye bye Cobra!


Bye bye Cougar!

I would so drive this right now. Hell, I'm pretty sure most Rivs would kill Honda boy. It's funny, on the way back to the parking lot on the bus I saw a lowered Civic bouncing over the rail road tracks and it sparked as it came down because it was so low. It bounced all over the place. Damn shitty little Honda! Probably cracked his side skirts! Can't be a true ricer without broken ground effects somewhere!

But yes, I believe that vibration is normal now that I got to thinking about it. Still doing better than the '97 Mark VIII we looked at a while back when we turned the key you could hear the rod knock. Yuck! And it had 79k miles! Tsk tsk tsk, Ford and their low quality cars (Especially that damned Mark VIII! I see more of those ugly things than our nice Rivs around here which sucks!).

Thanks for the tip Matt, I might give that a go sometime although I don't see how I could get a shift much tighter than I have already!

i think it started slowly like 2 months ago..when i tanked full my car at one fuil station. after that...when drived 50miph it made 1400rpm..and when a hill came..the engine started to ratle/vibrate...like it was shuting down...so i had to step more on gas so it shifted one gear down.
it dident do that when i buyed the car. had allways enaf power.

so now..it as cone enev more bad...it rattels/vibrates even more on 4th gear..
and on lower gears it as started to do the same thing...i was thinking that the fuil filter may be stuck...cos i have no idea when it last time was changed. or maybe a problem whit the ignision.
i buted new sparkplugs after i buyed the car.
broke one sparkplug wire...cos i cant get the parts so easely from here..i took one wire from another 3800engine..series 1...it was a bit thicker.
but still worked fine then.

anyways...now when i drive...i hear ratteling on +2000rpm...and the supercharger rattels tho...i truyed to make a video..so you could hear the sound...cant hear very good from it....on teh test drive when i made the video...the service soon engine started to plink :S...and then stayed on.
i drived carefully home..checked just incase all oils...and coolaint level...turned engine again on..but service engine light still is on...
shame i am so far away atm from unos garage..just have very bad luck...hope someone as any ideas what may be the problem.i will post the video here when its uploaded


its a 96 riv whit 140k miles

there might be a possibility that it is one of the transmission solenoids, im not sure just a suggestion. someone else will chime in