ryanakz1000

So I have a 1998 GT convertible that started to run rough when it got warmed up, this started happening as soon as I put on an o/r h pipe but was just a coincidence. It will run great for the first 15 min or so but then I got to step on the gas and the power is gone and the motor just kind of sputters and it wont accelerate worth a s@#t. So I'll stop and turn the motor off and re-start it and it seems to work fine for about 5 min then the problem is back. So far I've replaced the o2 sensors, checked/cleaned maf, replaced the egr valve and fuel filter. There are is no CEL on and it's driving me insane, any help would be appreciated.

jlharing99

I had a similar problem with a '95. It turned out to be the Upstream O2 sensors.

ryanakz1000

I've replaced those with oem replacements from the stealership and still did the same thing, i'm stuck.

petrock

When the motor warms up it goes into closed loop mode where the computer starts taking various sensors into account like the O2 sensors among others.

A common problem is people installing the up stream & down stream O2 sensors backwards. Not physically installing them into the pipe backwards, but installing the upstream O2 sensor in the downstream location, and the downstream O2 sensor in the upstream location. Or installing them in the correct locations on the pipe, but plugging them into the wrong connectors in the wiring harness. It will confuse the hell out of the computer and cause similar issues as what your seeing. I’d double check that first.

Good luck...