Hey everybody im kinda new to this site and not to sure how all this works, But I have a 99 Camaro 3.8 liter and I am having problems with it. A couple months ago it was miss firing while I was driving once in a while and my dad brought his computer to check it and it was throwing up an O2 sensor code. Then a couple months ago I was driving home and my car completely blows my head gasket so my dad and I fixed it then after we put the engine back in, it had a rough idle but it would run smooth. So he said get the O2 sensor so I did and we put it on and it still idled rough. So we then thought it was a bad coil so i got new coils and it still idled rough. Then we guessed it HAD to be spark plugs and wires so we changed those and that was just yesterday and guess what its still idling rough but now it will miss the ENTIRE time im driving it!!!! And I kinda hear something under the car everytime it shifts (hope its not my tranny) but my dad did tell me I might need a new catalytic converter. PLEASE I NEED ADVICE I LOVE IT TO DEATH BUT IM SO FRUSTRATED WITH IT IM READY TO DRIVE IT OFF A CLIFF!

 

Sounds like hes probably right, cut the catalytic converter off, and start it up like that. It will be loud and sound like chit and it will turn your check engine light on, but you should notice it running better immediately. New aftermarket cats arent too expensive considering you've already had headgaskets replaced.



edit- just noticed your from Ca, if you cut the cat off and start it to check it, dont drive it like that so you dont get pulled over and ticketed.


Also--- Welcome to the board.


Edit again--- You should be able to just unbolt the cat, Im not sure exactly how they set it up on the 3.8, but at least that way if it is bad you can "legally" take it to have a new one put on.

 

Nope, you cant unbolt the cat. Its all welded in together with the Y-pipe that comes off the manifolds. Its a $600 dealer part (mine was covered under warranty). Though Ive seen aftermarket ones as low as $300......though the CA approved ones are usually more.

 

you dont think it could be my throttle position sensor?? Or could it be both??

And yeah its welded all together and i found a universal cat for 84 dollars....

 

Nope, the universal cat wont work. I asked 2 shops to do it, and they wouldn't. Theres no room to weld after you cut the old one off since the bung for the o2 sensor is directly after the OE weld, and directly before the S-bend.

 

A good shop can make it work.....


On a side note, with everything that has been replaced, and the constant misfires, It was basically at times dumping raw fuel into your cat. Which WILL destroy a cat. If your CEL has ever flashed instead of just coming on then the computer has detected fuel at the oxygen sensor. It flashes to let you know that damage is being done to emissions equipment.

 

eggroll, you really should just burn that car to the ground...it wasn't meant to be

 

Engine misfires can be caused by a few things, loss of spark, air/fuel mixture is out of balance, or loss of compression. Fouled/damaged spark plugs, bad wires, or faulty coils can lead to the spark issues, but it looks like that can be ruled out due to those parts being replaced. A "lean misfire" can occur when the air/fuel mixture is too lean which can be caused by a dirty/inoperative fuel injector, vacuum leaks, exhaust leaks before the 02 sensors, or low fuel pressure caused by a weak fuel pump, clogged fuel filter, or a defective fuel pressure regulator. Finally, a loss of compression, caused by a damaged valve or head gasket can lead to misfires as well.

 

HEY IT WAS YOUR IDEA TO GET THAT CAR SOOOOO ITS NOT MY FAULT AND I KNOW I KNOW BUT ITS MY ONLY THING I HAVE FOR TRANSPORTATION RIGHT NOW AND NO USING THE EGGROLL NAME ON PUBLIC INTERNET

 

We checked my valves they are fine too my fuel sending unit is gone my car always says its full until its about to run out of gas then it will drop down to empty. but the whole fuel unit for my car is 500 + dollars its ridiculous. And since i have been trying to play cat and mouse with my car i've wasted 500 + dollars on it.

 

How did you go about checking the valves? Also, the fuel gauge on your dash has nothing to do with the actual fuel delivery to the engine. It does sound like there is an issue with float/sensor in the fuel tank and GM does sell it as an assembly, it is very expensive. To verify that you are having fuel related issues, hook up a fuel pressure gauge to the Schrader valve on the fuel rail.

 

took off the valve covers and checked them...my car is back firing now pretty soon i wont have a car that runs if i cant get a for sure answer on what is wrong with it =(

 

If the engine is backfiring, that could be a result of fuel issues. Did you do the fuel pressure check as I suggested? Also, what was the specific 02 sensor code you pulled?

 

you said it has a rough idle but runs fine have you checked the idle air control valve. That might be your problem

 

Check your cat.....