02 Trans Am LS1 5.7 running very poorly


Asked by Jan 04, 2014 at 10:40 AM

Question type: Maintenance & Repair

Hello all, Here's my question/problems.......I just bought a 2002 Firebird Trans Am with
the LS1 5.7 that has 135,000 miles on it from a guy who say's it just started all the
below problems just after he put fuel in  it and drove home, let it sit for 2 1/2 hours then
started it and this is what it's doing.........smokes a blue/white color and smells of (not
coolant/sweet) raw fuel bad, very rough running and will not idle unless I feather the gas
peddle...the exhaust tips have a lot of soot in them. No water(milky/brownish color) in
the oil, all fluid levels stay the same and no overheating! Appears there maybe some (I
can smell it on dip stick) fuel in the oil though! It seems like bank 1 is my trouble point
as if cylinders #5, #7 are misfiring or something........actually it's like bank 1 is
completely messed up, I can touch the headers after starting it and running it for a bit
and #1 is hot but as I make my way back to #7 they get cooler! I'm hoping it's a
clogged catalytic converter and thinking about unbolting from the header flanges to see
if that's it. I've not done a compression test yet but I will asap and I did put new MSD
plug wires on but #8 I can't get to yet.....the previous owner replaced spark plugs with
new NGK iridium's and MAP sensor.....I am replacing the MAF sensor and o2 sensors
but before I do this I'd like some opinions as I don't want to throw money at it, again the
compression test is the first on my to do list, any help would be so appreciated?

5 Answers


Oil looks normal but smells like fuel? Sounds like either an injector is sticking letting fuel enter cylinder while engine is turned off or a plug or two is not firing. Let it set for a while(over night maybe) then remove plugs. They should be dry. If any are wet or smell like fresh fuel that injector is probably the issue. Also could be just bad gas that fouled out the plugs on bank one.

1 of 1 people found this helpful.

It's hard to believe that all this is a result of gassing up the car and letting it sit for 2 1/2 hours. Blue/white smoke is oil getting burned. Gas in the oil is usually bad rings or cylinder scoring. Both are common in a 135k car that was driven hard. Your compression test will tell the story. Good luck!

2 of 2 people found this helpful.

dandyoun, thank's for the info and yes the oil looks good as a matter of fact he did say something about seeing fuel drip while looking into the throttle body/intake........and I have let it set overnight and #5 & 7 spark plugs looked glossy/shiny black coat on them and I've tried removing it but not all will come off...I've seen bad plugs from being to lean/rich but it looks like these were sprayed with glossy black paint!

2 of 2 people found this helpful.

Black is normally un burnt fuel. Try replacing the plugs. Also check the plugs for fire. They might not be firing for some other reason. Might want to turn it over a few times with plugs out to blow any excess fuel out the plug hole.

1 of 1 people found this helpful.

Blue smoke is oil burning. Which, BTW will kill the catalytic converter. If this engine has a heat riser it may be stuck open or the headers may/will be cold on the cylinders that aren't firing. Personally, with the age and mileage on this type of car I'd say it's time for an engine rebuild. Especially since it's burning oil. It's tired. HTH. -Jim

1 of 1 people found this helpful.

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