Motor Issues

[WYSIWYG]

Last driving to the Roll-In my '93 Cobra was acting up. When down shifting from third to second a different exhaust note(like a backfire), also the RPM would surge to 1500rpm. Then on the way home at three stops signs the motor just shut off, it restarted no problem.

It was warm last night 90 degrees, high humidity. I use 91 octane non-oxynated fuel (no ethanol). 18,600 miles. I have not changed the spark plugs& fuel filter in a while.

Some suggestions??

Thanks

 

[farmerjoe]

I had similar problem on my 90 gt and it ended up being the throttle position sensor.

 

[jpk92]

depending on how high your revs get when you down shift that might be normal.

Depending on your idle it could be a TPS sensor, IAC, EGR, Vacuum leak, that is what I see most often.

Good luck.

 

[kcp203]

If it only does this when hot it could be the TFI module going bad

 

[richstang]

If it only does this when hot it could be the TFI module going bad

sound likes the TFI module when it went on my car. I think you can have it tested at Advanced Auto. (make sure they get it hot by running the test numerous times. Mine only failed after it was heated up. Passed every time before. It will make you car do all kinds of crazy things.