I have a '99 GP GT w/ 3800 Naturally aspirated. All stock except air filter. I put in a K&N drop-in.

For quite a while now, it's been idling funky and stalling at times. The SES light wasn't on initially, but is now and indicates a MAF input low code. I have not pulled and MAF but a prior service shop did and cleaned it before the SES light came on.

Friday, it died when I went to lunch. When I tried to restart it, it ran really rough for a few seconds and blew white smoke out the exhaust. It seemed to clear itself up and return to normal after a minute or so.

Saturday night, it did the same thing. I let it idle for a bit. The white smoke was noticeable, but not thick. I had an '85 blazer with a blown head gasket. I remember that being very thick white smoke even at idle. It seems to drive ok, but the coolant low light is now on and my oil level is about a quart low.

I had the oil changed about 6000 miles ago (prob. 1-2 months) and had Synthetic put in. The oil looks dark, but not milky. I've had the plenum and lower intake gaskets replaced already and Dexcool was removed quite a while ago.

I've got about 206K on the car. I should add that it has NEVER overheated on me since I've owned (since about 35K miles). When the upper plenum was replaced about 3 years ago, the engine did lock up due to coolant in the cylinder, but has been fine since.

My hunch is that my head gaskets are starting to fail since the intake gaskets have already been replaced.

Thoughts?

Thanks in advance.

Unplug the MAF and see if it still does it. If it says something is wrong with the MAF, start there. Hard to trouble shoot an engine that has something else wrong with it.

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2004 Impala LS - got some mods
NAIOA Moderator

Making you think twice before picking on Impalas

Sounds like when my MAF died....note, when I unplugged it, my problem still exsisted

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2002 GT...Wizardair, ZZP 2.5 o/r dp, Special Eddition two-tone leather interior added, HUD added, 12" Brake Upgrade, ZZP strut tower bars, gmpp sway bars,-6an braided SS fuel hoses , Hptuned, Top Swaped.....
I've got Boost!! I've got only 1.5* KR left my poor L36 block.....

Unlugged MAF.

Idle got a little better, but now it hesitates when I step on the gas.

Also, when I started it up this morning, the white smoke from the exhaust got thicker as the car warmed up. As it warmed up, the exhaust started to smell more sweet.

You probably have a failed LIM gasket that's letting coolant into a cylinder through the intake runner. Your MAF may also be bad.

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2004 Impala LS - got some mods
NAIOA Moderator

Making you think twice before picking on Impalas

Thank you. I dropped it off at a local mechanic yesterday. He seemed to think it was not likely the head gaskets and more likely the LIM gasket.

There was no presence of exhaust in the Antifreeze and no Antifreeze in the oil. It was a gallon and a half low on antifreeze though.

I tried to pull out the MAF the other day to clean it only to find out I don't have the right torx driver to get it out.

Thank you for the help.

A gallon and a half!!! Thats nearly half your cooling capacity. That coolant has to be going somewhere. Was there anything in the radiator at all? Did the mechanic tell you that there was no exhaust gases in the coolant and no coolant in the oil? If so, how did they test for this?

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Scotty Hall
Bartlesville, OK
2001 Pontiac Grand Prix GTP
It whines a lot, but I like it.

The only limitation you will ever face in life is yourself!

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2.8 Pulley, Intense IC, P&P Gen V, Machined Intake, Intense PCM, 65lb/hr Injectors, N* Throttle Body, 1 3/4" Headers, 3" Exhaust, Intense Shift Kit, 3.69:1 Gears, 4000 Stall, N20

I'm not sure how he tested for the exhaust gases, but he did a pressure test and put 18psi against the cooling system. He checked yesterday, then again this morning. My wife just drove it to school (18 miles) and said the low coolant light was on again, but nothing coming out of the exhaust. Ill have to look at it tonight when she gets home. I may take her some antifreeze just to get it home.

This is somewhat troublesome since I have to drive 60 miles to and from work on a daily basis with very few towns in between.

Yeah, when ever you see the thick white smoke out the tail pipe you are burning coolant. You said you replaced your upper plenum 3 yrs ago, that is a long time it could be bad again due to its inherently flawed design, not to mention some replace the original with an oem or even a used one. Plastic.....need I say more. Also, like other members have said it could be the lower intake gasket, also made of plastic

Either way, let us know what it was.

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3.4", 3" cated DP, SLP Air box, TB spacer, 180* Thermo, "Bilemke Tuning".