Sputtering when Accelerating

[Smucky]

I have a 2002 Regal GS. From a dead stop, nothing is wrong. But when I'm moving and I want to accelerate hard, I push the pedal to the floor and the car just sputters and pings loudly. I have taken it in, and the guy hooked it up to read if there were any notifications. There was nothing. He said it's probably an internal problem, and if the "check engine" light comes on, there's nothing that can be done (except take out the engine). He told me to use 91 octane gas for a while, and see if that helps. I usually use 89.

Could it be the fuel filter? Spark plugs? gas?

Thanks for your help, I'm glad this forum is here.

 

[HotZ28]

Welcome to the forums. How many miles on this engine? Does the engine consume any oil, or coolant? You could have secondary ignition misfire (coil(s), wires, plugs) or some other problem, but the symptoms sound like a clogged cat. To eliminate, or verify the cat as being the problem, you could take it by a muffler shop and have a back-pressure test performed. If you have a vacuum gauge, you can test it yourself. Hook the vacuum gauge up to one of the manifold vacuum lines and start the engine. A normal engine should pull about 20 in-Hg. While observing the vacuum gauge, rev the engine up to 2000-2500 rpm and see if the vacuum holds the original reading, or if it drops. If it drops 4-5 in-hg, you have a clogged cat.

Understanding the Catalytic Converter

 

[Smucky]

Thanks so much for your help. It has somewhere in the neighborhood of 129,000 miles. I can't tell because the light is out. My mechanic says the whole dash has to be replaced to fix that. Anyway, it doesn't burn oil, though it has a slow leak. It does need coolant from time to time.

Thanks for the advice. I'll take it to a muffler shop and try what you said.

 

[Laxnut]

I second that, sounds like a clogged cat. That causes all sorts of engine problems.

 

[xstickx]

There are very few engines out there that actually call for higher octane fuel. Read your manual. I'm almost certain it will tell you to use regular unleaded fuel (87 Octane). As for the sputtering, yes a clogged catalytic converter could cause your issue, but my first check would be fouled plugs and faulty wires. Sputtering during acceleration is almost always cured by plugs and wires. Start there. It's much cheaper than a catalytic converter.

 

[kdubb]

the GS version should have 91 or better in it. the earlier year models have premium only labels all over them.

the dash does NOT need to be replaced. there are DIY write-ups on how to re-solder the loose connections on the board and have a perfectly working dashboard again for pennies to the dollar of a shop repair.

agree that CAT could be problem....but you could also try driving the car with the supercharger belt removed from the vehicle. see if you still get the sputtering. maybe its boost related

 

[buickfan235]

Agree with xstickx. I'd take it to a mechanic just to be sure it nothing serious

 

[SwitchPitch]

Anything new to report Smucky?
And just out of curiosity, when it does this can you feel it downshift to lower gears like normal, or does it just sit there at the same rpm and "try" to accelerate without downshifting?

Hope you got it fixed though. Been awhile and it sounds annoying.

Paul

 

[SwitchPitch]

Subscribing to hear (hopefully) the answer. Have an '03 LS doing the same thing. No supercharger to put in the mix though, so mine should be simpler.
Had come to the same conclusion on the exhaust, so am going to take it to a shop tomorrow and see what there is to see.

Paul

 

[SwitchPitch]

Oh, I should mention that I did have a friend feel the exhaust when I revved it up. At idle it does feel extremely weak, but with some revs, he said it did feel pretty "normal" for what it's worth.

Paul

 

[SwitchPitch]

Sorry to keep hogging the thread here, but post-whore that I seem to be, I thought I'd at least let you know that a new cat fixed my issue completely.
Low vacuum, retarded timing, no power, surging when accelerating and the trans shifting at strange points, all indicated, among other things, a possible clogged exhaust.
We didn't perform any testing other than the old "hit it with a hammer and see if it rattles" type of exhaust test, but a quick sawzall job took the cat off and it was clear that it was all clogged up with debris of some kind. Looked more like a filter had caught bits of piston crown(!) than a typical fuel-related clogging. But hey, the exhaust guy said it was pretty normal looking for a clogged cat, so I'll worry about other collateral damage later.
When it fails...

Good luck with yours.

Paul

 

[HotZ28]

Sorry to keep hogging the thread here, but post-whore that I seem to be, I thought I'd at least let you know that a new cat fixed my issue completely.

Thanks for the update, most people do not bother to inform others with the resolution of their problem. Since we have never heard back from the OP, I have to assume he/she had a similar problem with the cat?? The most common reasons for CAT failure is, valve guide leaks, coolant ingestion, & running too rich on the fuel curve/trim.

 

[G-881538]

Thanks so much for your help. It has somewhere in the neighborhood of 129,000 miles. I can't tell because the light is out. My mechanic says the whole dash has to be replaced to fix that. Anyway, it doesn't burn oil, though it has a slow leak. It does need coolant from time to time.

Thanks for the advice. I'll take it to a muffler shop and try what you said.

Whole dash shouldn’t need to be change maybe, I had the same problem with the prindle myself, there’s resistors on the back of the speedometer circuit board, if u remove it and open it up, u should find the resistors on the back, they may look fine also but it’s u lightly touch them they should just pop off meaning on side of the resistor came disconnected, buy sum 150 ohm resistors (I think) and solder them on the back and it should work again

 

[G-420307]

I replaced the turbo in my 2012 gs and busted one of the cats out also but only the one in the middle of the car, im wondering if there is 2 and the other might be clogged. It tells me my bypass valve is stuck open on the check engine light but not real sure