OK guys, here is my problem. I just got my eclipse back from the body shop and it has a rough idle and if you tap the gas and let off at like 1500rpm, the rpms climb to about 2000 before dropping down. I just changed the plugs for NGK V Powers. I don't have any CELs. I just put on my Megan Header and a friend and I did the Megan cat-back before it went to the shop. When we were putting in the cat-back we could not break the bolts loose off of the catalytic converter from the eclipse even with an impact, so we dropped the whole center section in one shot and I used the old cat from my avenger and I bought both new oxygen sensors for the eclipse because they were rusted too. I had just had a remanufactured motor put in the avenger and it was stumbling around. On the avenger I had changed plugs, wires, egr, iac and coil. Still stumbled around. The eclipse almost sounds like it is choking itself out and it smells very gassy. I was wondering if my cat could be bad. Would shining a flashlight through it let me know if it is bad?

-Nate
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-97 Avenger I4 5spd (R.I.P.)
-95 Eclipse GS 5spd
-Mods: Bosal Header(soon to be Megan 4-1), Megan Racing Cat-Back, Toucan CAI
All-Motor Buildup on the way

I dunno about the flashlight in the cat thing, but I bet dropping the exhaust from the cat back and testing your throttle blip would tell you if they're related. Aside from that, I think it sounds like a vacuum line issue. Double check all your vac lines under the hood. The engine is still getting some air once the TB snaps shut imo.

Originally posted by DR1665
I dunno about the flashlight in the cat thing, but I bet dropping the exhaust from the cat back and testing your throttle blip would tell you if they're related. Aside from that, I think it sounds like a vacuum line issue. Double check all your vac lines under the hood. The engine is still getting some air once the TB snaps shut imo.

I just checked the vacuum lines and they all look good. It doesn't really surge at idle, it just makes a putting sound, and I can definately smell gas. It also has a slight white smoke that smells like gas. No CELs, it sounds like it is choking itself. Could a bad cat maybe make the revs hang because it can't get rid of the back pressure quick enough?

-Nate
________________
-97 Avenger I4 5spd (R.I.P.)
-95 Eclipse GS 5spd
-Mods: Bosal Header(soon to be Megan 4-1), Megan Racing Cat-Back, Toucan CAI
All-Motor Buildup on the way

Let me know if you find a fix, because mine does the same thing.

Originally posted by 98VengeI4
Could a bad cat maybe make the revs hang because it can't get rid of the back pressure quick enough?

Your guess is as good as mine. The only other thing I can think of to test this theory is to cut the catback loose and see how she idles/runs. :shrug

I am planning to try this tonight. I just am not looking forward to dropping the cat because with the cheap gasket I got those bolts are tight as hell and hard to take out, and I don't have an impact. I might just put on the other new gasket I have while it is out because it should fit up to the bolts better.

BTW.. I noticed last night on the metal tube that goes from the EGR to the intake manifold one of the bolts was sticking out maybe about 1/8 of an inch, so I tightened it down. Still puts. Also, I noticed the cam sensor seal bolts were not tight either. I just got this car, so whoever did work on it before me must not have done a great job. I need to buy a new inner boot for the drivers axle, and I also need a new inner boot for the cavalier I have too, but for the passenger side. This is after we just put a new split one on the outer passenger side of the cavy.

-Nate
________________
-97 Avenger I4 5spd (R.I.P.)
-95 Eclipse GS 5spd
-Mods: Megan Header ,Megan Racing Cat-Back
All-Motor Buildup on the way

I just ordered an egr gasket for my new egr valve I had on the avenegr. I am trying to talk my friend in to helping me take the cat abck off tonight when he gets off of work.
I will figure it out, it is just a matter of double-checking things.
I just hope it is not the head gasket. When I was under the car doing the header I saw oil all over the wires behind the block. It was not running so I don't know yet if it is leaking or if it was fixed. I had my fair share of headgaskets go in these cars.
-Nate
________________
-97 Avenger I4 5spd (R.I.P.)
-95 Eclipse GS 5spd
-Mods: Megan Header, Megan Racing Cat-Back
All-Motor Buildup on the way

Okay, today we took the cat off. The cat looks fine. Next thing I will try is a new TPS along with my iac valve from the avenger.
-Nate
________________
-97 Avenger I4 5spd (R.I.P.)
-95 Eclipse GS 5spd
-Mods: Megan Header ,Megan Racing Cat-Back
All-Motor Buildup on the way

Going to order thottle body gasket tomorrow along with the new tps. Should have it Sunday. Does anybody know what size the iac o ring is? I want to get a new one.

Oh, and as far as I can tell I am not leaking any oil so they must have fixed it, just need to get all of the old crud off of there.

-Nate
________________
-97 Avenger I4 5spd (R.I.P.)
-95 Eclipse GS 5spd
-Mods: Megan Header ,Megan Racing Cat-Back
All-Motor Buildup on the way