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Engine go put-put-put-glug-glug-glug - Muliple misfires - lost 03 GP GT

jcgre3n

jcgre3n

New member
2003 Pontiac Grand Prix GT 3.8 NA

Was sitting in stop-and-go traffic and tried to accelerate. The engine sounded like it was drowning and was not accelerating much at all, and I heard someone else say, "what's that smell??!"

Check engine code is telling me Multiple Misfires, so I pulled and tested the coil packs, they're fine. Changed the plugs and wires, and it's still doing it. Once up to speed I can stay up to speed, but it accelerates very slowly. The car is also burning through about 1/4 tank of gas a day. There's a slight squeal in the engine, like a belt squeal, when I accelerate from a stop, but after the car gets going faster than 10-15 MPH the squeal stops. Car leaks oil and engine coolant, but not a lot (could be unrelated) and I can't see from where. Radiator has some brown gunk on the cap and in the tube (probably also unrelated). The engine does not overheat. Prior to the issues, I had a check engine light for the rear O2 sensor, never got around to replacing it. I had my fiancee following me while limping home, she said my car smelt horrible. I smelt something like a slight burning of rubber, and she said the car smelt a little rotten, but also like burning.

Plugs and wires usually solve this issue, however, they did not. Now I'm lost. Any ideas?
 


Where in MN are you?

I'm willing to bet because of that bad rear 02 sensor its dumping fuel like crazy and it plugged up your cat converter and thats your problem.
 
Fivefingerdeathpunch said:
Where in MN are you?
Click to expand...
Edina/Lakeville/Edina/Cottage Grove area...so basically southern metro. I work, live, and have family so I'm in any given area throughout the week.

Thanks for the cat suggestion. I figured it was either that, or the timing belt, and I was desperately hoping it wasn't the timing belt.
 
Yup, may be the O2 sensor. If you have a OBDII scanner (depending on which type you have) You could read the O2 voltage which should be no less than .2v and no more than .9v. And remember, the cat usually dont go bad on its own( usually burning oil, unburned fuel, incomplete combustion, coolant getting in there, too rich, bad 02 sensor, etc. causes the cat to go bad) But as mentioned, its probabaly the O2 sensor but dont go swapping out the CAT or anything else without finding out the source of this issue, otherwise your new CAT and whatever else you buy would just go bad also....
 


The O2 sensor has been bad for months, I just didn't give much care to it because it was a sensor. Now I know I should probably take care of that sooner should it happen again.
 


the N/A engine is known for the upper intake manifold gasket to fail, when it does, it dumps coolant into the engine oil, and kills your engine, most call doing the upper intake and lower intake manifold gaskets maintenance, due to the old plastic gaskets failure rate. and peace of mind.
 
yeahh, scott its not the gasket that goes bad, its the whole upper intake.

If you go through Bill's thread, you will find that on an n/a engine, there is an egr stove pipe that is presses into the lim, this pipe goes up through a tunnel into the uim (upper intake manifold), on each side of this tunnel, there are two coolant passages to allow coolant up into the throttle body to keep it cool...honestly doesn't help in my and most peoples opinions. After years/milage....the egr tunnel goes through many heat cycles and wears through to the coolant passages because the stovepipe is right against the tunnel.

The revised Dorman Intake Manifold ( PN# 615-180)...which can be purchased at most every parts store, most all of them will have it in stock, comes with a new stovepipe that is the same base diameter to be pressed in the lim, but has a smaller pipe diameter as to not be so close to the tunnel walls.
 
Almost got it all Mike. The coolant is for keeping the TB from icing at the north pole. Which I've never heard of it being an issue and for how little coolant is in the TB.. it's sad.

The replacement UIM's can still have the issue. It's all about heat cycles etc.
 


You'll all be happy to know that it was a fried circuit on the board that the coil packs plug in to, not a clogged cat. However, I still have the vanishing engine coolant issue, which I'm guessing is my intake gaskets leaking. The gunk on my radiator cap is actually oil mixed with coolant and water, which is also an issue (probably relating to the gaskets on the manifolds as well).
 
Oil cant get into the cooling system, but trans fluid can from the side trans cooler tank on the rad.

Or it could be that the air in the coolant system mixed with your dexcool and sludged it all up.

If you ever wanted help doing those intake gaskets I might be around to lend a hand, but you might be a far drive.
 
So it was an intermittent problem? Thats always the main issue when you cant find a problem, some damn wire somewhere.....

Was the ICM affected in any way?
 
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