So 700 dollars later with countless hours of diagnosing and still no fix on why my idle is totally screwed up. I randomly decided to purchase a used corksport 3 inch turbo back exhaust and installed it. and INSTANTLY my idle is back to normal with no misfire or horrible gas smell...apparently my stock cats rotted and clogged to hell. which is probably the reason for the awkward idle and smell.

ARG!!!! IM A SHITFACE!!

We should add that to the list of idle troubles.

CLOGGED CATS WILL SCREW YOUR IDLE UP

 

what did u spend $700 on???

 

Sweet.

 

TPS, AFM, GAS (ARG!!! 10mpg), coils leading and trailing, plugs, wires, injectors, seafoam with oilchange, and the exhaust system.

 

Damn son. I feel you. I'm going through the same crap with my DD. It's a big *** turd of a 240. But your recent revelation has lead me to figuring out why my car is being such a big piece of crap, and I think that cat is choking my car.

 

MidnightOwl do you have a vacuum gauge. A clogged cat will cause low vacuum readings and vacuum will get lower while you increase the rpm. Low vacuum will be sensed by the map as more of a load on the enigine more of the load will cause it to add more fuel, normally. Being that i dont know our engine management system, i would guess this has a little effect because we use a map and vane airflow meter. Either way your fighting a restriction which will require more gas. WingsofWar glad you found the fix and now you have a sweet exhaust to go with it, watch out for boost creep now that you've freed up the exhaust

 

hmmm that kinda sounds like my car... rough idle smell of gas bad mpg... thanks for the tip!

 

while I was at it i ported the wastegate and added a RB FCD hurrah..

 

I do believe my 87 GXL is experiencing the same issue. Ill switch it up and see if it helps. Thanks for the info.

 

I had an aftermarket cat clog while driving on the highway... car kept losing power until it had just barely enough to idle. I pulled over and heard a hissing, and checked all of my tires for an air leak to no avail. Turns out the backpressure was so high it was literally pushing exhaust out the mating clange at the stock manifold-downpipe. It sounded like a leak on an aircompressor fitting.