Question : real bad problem! rotten egg smell

[rsf98]

2003 pontiac grand am
3400 v6

so the other night my car started running very odd out of nowhere.
couldnt get above 20kmh then it backfired and i got all my power back for like 10 seconds then went back to running like crap

at idle it will bounce around and sound like it has a big camshaft

exhaust smells like rotten eggs. exhaust tips turned white

at idle all i can hear is the CAI sucking air like crazy trying to breath!

took the car to mufflerman and they said it was the ICM so i changed that and still no change its still doing it!
engine throws a p0300 code mutipule missfire detected

i want to say its my cat converter. am i wrong?

any help appreciated!

[bszopi]

Yes, it is most likely a clogged cat converter. Bang on it with a hammer and you will probably hear stuff bouncing around inside.

[rsf98]

just knocked on it.. no rattles...

[robertisaar]

cut it off anyway. is it the original one? and thats about the only thing that will make that nasty sulfur smell....

[rsf98]

so we've cut the cat off.. and no change. still idles like a drag car and give it gas and have no power. just wants to shut off... could this be a fuel pressure problem?

[bszopi]

How old is the fuel filter? I'd look into cheap things first. But, you can take off the vacuum line from the FPR and if fuel comes out, then you know that is bad as well.

[rsf98]

fuel filter has been changed pretty recently and tried the vacuum line on the fpr and no fuel comes out

[robertisaar]

can you smell fuel there?

[rsf98]

smell fuel at the fpr?

[robertisaar]

smell fuel at the fpr?

yes, it might not actually gush fuel out if you pull the vacuum line off while running, but you may get a whiff of gasoline, telling you its not completely FUBAR yet, but it will be soon

[rsf98]

unplugged the MAF sensor and it runs like a champ right now

[robertisaar]

well i'd say you found your problem.. but isn't the MAF and IAT connected on the same plug? if so, its going to be running rich until you either get the MAF replaced or at least hook up the IAT

[rsf98]

iat and maf have their own connectors... but yea it may run rich until the maf is replaced....thanks for the help though i appreciate it

[robertisaar]

no problem, thats what the community is here for...

[60dgrzbelow0]

Are you using any engine oils that are designed for racing engines, like Valvoline Racing Oil? These types of oils have fancy, metal hardening additives like Zinc Di-Alkyl Dithio-Phosphate that do wonders to protect metal parts from wear...but play havoc on heated O2 Sensors and wind up coating the Platinum Screens in Catalytic Converters, rendering them clogged and useless. In some cases..the residues can emulate the chemistry of Hydrogen Sulphides and hence...the smell of "Rotten Eggs" (By the way...Inhaling too much of this gas is toxic). Hope this is the case, because the solution is very simple: Just stop using any motor oils with these exotic additives...