1997 mustang cobra problem please help

1997 mustang cobra 65k miles runs and starts fine runs on all 8 cylinders the put if nowhere it only runs on like 4 cylinder me or so

I have replaced the New plugs, plug wires, coil packs, connectors to coils please help

Thank you

Blown_By_You said:

www.hookedonphonics.com

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LOL

Use a OB2 scan tool and look for codes.

Nothin comes up when we scan it

Blown_By_You said:

www.hookedonphonics.com

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If you’re so smart from being on hooked on phonics as a young kid to an adult u would know what’s wrong with the car smart guy

Phillip Scocca said:

If you’re so smart from being on hooked on phonics as a young kid to an adult u would know what’s wrong with the car smart guy

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I'll rephrase for him in a slightly more tactful way:

If you want help from a forum that uses words to communicate it would be best if you chose your words thoughtfully and clearly presented the problem and possibly what you've tried to remedy it.

nobody wants to whip out a Rosetta stone to try and help a guy. help us help you.

I start the car it runs perfect then after a few minutes it runs rough like it runs on half the cylinders the check engine light comes on then off I put my tester in and it reads nothing no codes , I replaced the wires, coil packs, spark plugs, connectors to the coil packs none of that helped and I’m stuck now I’m not sure what else to try

Not an expert on code readers, but I think some readers can access older codes even if the engine light has gone out. In other words, if the light has come on and then gone out there should be a code in history that some reader can show.

Question: when it starts running like crap if you floor it does it get over itself and rev good?

If yes then I think you've got a bad 02 sensor. its perfect at startup right? then the sensor heats up and the pcm starts trying to use it but the sensor is fragged so the readings are bad so the computer probably tells the injectors and coils to do the wrong stuff.

your front O2 sensors do this (before the cats) so I would replace them and see what happens.

the same thing happened with my 94 f150 with a 302, it would stumble and when i floored it the truck would run like a scalded dog. it was very strange but a new 02 sensor fixed her right up.

Also inclined to agree with O2 sensor but it should show a code.

Take it to a parts store and have them uabj the codes. Some stores have better readers than others.

When I rev it it dosent change at all it dosent get over itself very strange

unplug the maf and start the car. tell us what happens.

Okay will do I’m in PA now I will be back Saturday

cool. BTW when you revved it did you go wide open throttle? because you have to do that for it to switch to the fuel map and stop using the O2 sensors.

Yeah it was revved all the way to the floor no change

I hope it’s not like a dead cylinder or anything the cars all stock

and it runs perfectly fine when cold?

On start up it runs good hot or cold then out of nowhere is does it gets weird