FAQ: Hesitation, Stutter(Studder), Shudder, Stumbling, on Acceleration/Load

ok now its been 1 week i have been trying to fix this problem.. and i gave up so i finaly took it to a mechanic.... here goes the story
so i tought i would chage the plugs and wires on my rivi so i did... for 2 days it was fine... but then when i got in the freeway whne i was hitting over 70mph.. the car seem to shake alot when i would press on the gas... i mean really shake and it wouldn accelerate nor the rpm would go up... then the SES light started flashing.... so i checked the plugs and wires and they where fine... i have sutolite 104s plugs and oem wires.... so i took off the laugs again and wires.. did eveyrhting again.. and still the same problem... now it makes dis loud noise like in the engine close to the supercharger.. LOUD noise.... so i took it to a mechanic near where i live.. on the way over there it was worst.. on the red light my car shakes alot.. almost like it wants to turn off..then when i accelerate.. it shakes like hell then takes off then .. when i press on the gass it shakes and doesnt want to take off and the SES light comes flashing again.. and makes and even louder noise..The worst part is that i just called my mechanic and he said he checked the wires and plugs.. he said they where fine.. he said that he thinks its the supercharger but i highly doubt the supercharger wont let my car accelerate and would make it shake like that.. pls help!!

it's possible you are dealing with a bad supercharger tensioner, take the SC belt off and see if the tensioner swings freely and has some good resistance on it. Watch it from under the hood with a quick heavy throttle blast at idle and see if the belt tensioner moves normally.

It sure sounds like plugs and wires or a spark problem though, maybe you have a coilpack going south on you? You should get a PCM code for an ignition problem though.

Here's another thing to try: Take the S/C belt off (you can't take it off completely because it's threaded through that side engine bracket). Don't worry, the car will run just fine with no S/C belt, it'll just be slower. Try all kinds of throttle positions. If it's smooth, your problem lies in the S/C.

My guess is still ignition, because you said it now runs poorly at idle, there is no S/C use at idle.

I cracked a spark plug while installing it and had a problem similar to what you are describing.

eyah my mechanic said it was the supercharger tensioner.. but i tought it was weird that as soon as i changed the plugs and wires this happened... yeaH I TOUGHT ABPUT TAKING IT TO AUTOZONE TO SCAN IT... I HAVE NOT DONE IT YET..^^ thanks alot for your input.. i will try that todaY...

2toneRivi wrote:

eyah my mechanic said it was the supercharger tensioner.. but i tought it was weird that as soon as i changed the plugs and wires this happened... yeaH I TOUGHT ABPUT TAKING IT TO AUTOZONE TO SCAN IT... I HAVE NOT DONE IT YET..^^ thanks alot for your input.. i will try that todaY...

is there a SES light (service engine soon) >?

yeah!!!

2toneRivi wrote:

yeah!!!

well yah get er' scanned and let us know the code man..........

Quote :

Take the S/C belt off (you can't take it off completely because it's threaded through that side engine bracket). Don't worry, the car will run just fine with no S/C belt, it'll just be slower. Try all kinds of throttle positions. If it's smooth, your problem lies in the S/C.

Not necessarily true. If it's ignition related (I think it is), when you run without the blower belt there will be no boost, so the PCM will not engage the higher spark tables. If the problem only occurs under load (in boost) it doesn't mean the blower is the problem; it probably means the wires, coil, or plugs are bad. You can't always tell by inspection, or by resistance. If any part is old, it should be replaced, starting with the least expensive components.

^^ THANKS AARON.. yeah i just went to autozone and i have to borrow the obd2scanner.. so tomorrow im going to go for it... but im looking at my ignition coil.. and its the stock ones.. and the car has 125k miles on it... they have the msd coils at autozone for 46 bucks each one.. i think im going to go ahead and buy them.. what u guys think??

Go OEM. From what everybody says, they're the best.

hey mann im tired of searching it... whats PCM?

Pcm is powertrain control module..controls shift points , Air fuel ratios , ignition timing etc.

I didn't make it clear in the above post... I'd still recommend running with the belt off. If the symptoms disappear, there's a good possibility it's spark-related.

The symptoms especially the flashing check engine light lead to something ignition related.

I would check all plugs to see how they are burning and also check all the coils.

AZ should be able to read the codes in their parking lot in two minutes.

yeah they did not want too.. they say i have to leave 1 170 dollar deposit to borrow the scanner .. and ill get my deposit back once i return it,... just to make sure.. the front plugs are 1-3-5- from passenger to driver side.. and back plugs 2-4-6 from passenger to driver right???

i have been driving my 72 cutlass for about 2 weeks.. and i already pumped about 250 dollars of gas... just going to work.. i need to fix my rivi asap.. lol

You are correct on the plug locations.

i got the code!! its P0300.. it says random/multiple cylinders misfire.. what yall think what can i do??

2toneRivi wrote:

i got the code!! its P0300.. it says random/multiple cylinders misfire.. what yall think what can i do??

which cylinder was the culprit of the misfire.......... mine was number 4 ( rear middle) i hated that cylinder, i wish it would die....... AHHHHHHH or not

a faulty MAF can cause random missfires and the symptoms you're describing. have you cleaned it recently?

got.. it.... it was cylinder #6.. and i think my coil is not working properly....hey caN I ONLY CHANGE ONE SPARK PLUG... OR DO I HAVE TO CHANGE ALL OF THEM... SPARK PLUG NUMBER 6 LOOKS BURNED OUT

they are only 1.50 each might as well change them all, unless they are new and you're sure they are in good condition.

yeah i just changed them all... and its set.. just trest drove it and its fine!!!!!!!!!!!!!!!! thanks aloot... and that mechanic tried to make me change my supercharger tensioner... and no i havent cleaned my MAF sensor... i dont know how to take it off.. honeslty this is the first time im doing some mechanical work ohter than changeing the brakes.... thanks for all ur help!!

i have question about the response of my riv.why is it when i floor it it has a weak response any 1 else had this before please help thanks

what year ? what type of engine? and what kind of fuel are you using?