Thread: sputtering under load

So about 2 or 3 weeks ago there was a mistake and about 1.5 gallons of 87 got put in my car, Topped it off with 20 bucks of 93 and put some STP octaine booster in, started driving, and under heavy load with no boost like going up a hill it was sputtering and backfired once..

Babyed it around and burned off half the tank, still sputtering under heavy load like trying to go from 60-65mph it would just loose all power and id have to back off the gas and then give it a little bit more throttle and it would go.

Iv used up all the gas, put a fresh tank of 93 in, changed the fuel filter and cleaned the maf.

Its still doing it.. Im thinking the cats stuffed up. I drove it around tonight to get it hot and checked if it was glowing.. it wasnt a light blob but it was a little discolored and there was a spot on it blacker then sin, right where it connects to the downpipe.

Cars stock with a ported blower and CAI.

Thoughts?

Can you not get the car above a certain RPM range? Usually this is a sign of a clogged cat. If you suspect this, try dropping the exhaust loose and see if that changes anything. It will be louder than you know what, but for a short test drive you could get away with it.

Originally Posted by footballplaya3k

I had the same issue when I had bad plugs

got brand new plugs and wires (well about 1k miles) but yeah.

I have to put maybe half throttle to get it to go over like 3k rpms i think?
I feel like somethings choking the motor..