HELP!!

[blackdogxj]

Here we go..i got a 97 XJ 4.0 with a 5 spd.

problem #1...keeps throwing codes for the oxygen sensor..put 2 new sensors in it and still throws the code for the one thats in the cat.

problem #2...when it runs for a bit and gets warm, it wont stay idleing

problem #3...when i pull out after it warms up it will stumblem on its self, then pick back up.

problem #4...when i put the clutch in the idle goes to 2000 rpm without me touching the gas pedal.

now my teacher in school is sayin that F.R.E.D might be messed up inside thats y it keeps doin that stuff...
i had fixed the signal wire from the rear oxygen sensor (it was rubbed through)

any thoughts, comments, suggestions would be great.

thanks
Brad

[jeepdude10000]

have u checked the cat?

[blackdogxj]

i did check the cat...it did the same thing before i punched it out...once i punched it out it didnt change anything...my teacher said it shouldn't matter if i did that.

[jeepdude10000]

the sensor behind the cat needs to read different that the one before.
I have seen a thread or tech on a way around the rear sensor. dont remember where.

[blackdogxj]

ive heard numous things, sensor simulators, or rasing up the o2 sensor that way it just gets a small sense of the exhaust going threw the system. do u think that would work?

[Matthew Currie]

Have you checked all the pertinent wiring with an accurate ohmmeter? Especially if you did have a problem with the wire already, there might be another. If you can, test it when it's hot. Sometimes a bad splice or a corroded connector, etc., can get worse when it heats up and it can be a bear to hunt down if it doesn't show up cold.

Finally, (just in case 5-90 is still asleep in his time zone) have you checked thoroughly for vacuum problems? Put a gauge on the manifold where the main line for the reservoir taps off.