Rex7-93

Ok. About a month back my car had problems with hesitating, and popping/backfiring in certain gears and rpms. I first thought fuel system problems, but then came to the conclusion that it was a clogged precat/maincat. so i replaced the dowpipe and gutted the midpipe and it was all better. No problems. so yesterday i got up and drove my car and it did the same thing again. I took the maincat off and found a large piece of catalyst stuck in the outlet of the maincat. so i thought cool. all fixed. so i went to drive it and the problem persists. could it be a fuel system problem. HELP!!!

Rex7-93

Anyone have any ideas. I'm working on buying the Power FC but until then... I need help!!!

qwester007

iTrader: (3)

If you have removed all of the cats and the car is running rich- this will happen. After modifying your exhaust your car will dump alot of excess raw fuel into the exhaust when you abrubtly get off the gas- sometimes causing backfires. As for running poorly, you will have to get the car tuned and you would definitely want some kind of adjustable ECU.

Kento

If you actually found a chunk of the catalyst broken off the main brick, there's a good chance your main cat is toast. You might want to take it off and examine it more carefully to see if it's intact.

Rex7-93

i had the cat itself off and it loooked to be intact. i had been running for a while with the downpipe and gutted cat with no problems so i dont think that it could be that.

Kento

Nevermind, didn't see that you had "gutted the midpipe".

Depending on how well you gutted it (flow) and if you're still running the stock ECU, you could be experiencing a lean condition at certain throttle/rpms. Hesitation and popping/backfiring can also be caused by running too lean.

Rex7-93

I Have started to notice that it is not really at a set rpm but anytime I give it just a bit too much on the throttle it will hesitate slightly and pop extremely loud. This causes me to believe that it is not recieving adequate fuel. Clogged Fuel filter? Stuck injector?Bad fuel system? I have no idea, And i dont know what to do to figure out what is causing this. Has anyone else experienced this and knew that it wasnt a clogged cat, but did know what it was and how to solve it. This is driving me crazy.

Kento

If you're running a gutted cat with the stock ECU, I think you should stick a stock or hi-flow cat on there and see what happens.