I HAVE searched & found no help.Please,don't try to "rip me a new one".

What would cause my 98 XJ to surge @ a redlight?It only lasts like 1 sec.
It also acts up around 1600-1700 RPM's.Feels like the trans. is slipping but you put it in nuetral @ it still fluxuates RPM's.

What's wrong?

 

Do you have the A/C on?

 

No.

It is a 4.0,auto.; if this helps.

 

When I had this problem I had P0171 code which meant that the PCM was reading a lean signal at the 02 and correcting it the richening the fuel mixture.

02 sensors that need to be replaced can cause this. For example, I went wheeling and submerged the tailpipe in the water. I never got a code for it because it still worked within the normal voltage range... but the computer doesn't monitor how fast it responds. They send signals many times a second. When they get wet it messes with the operation and puts it out of sync with the one in the front which is operating fine.

However you could also have a vacuum leak or a bad TPS. They will also cause that.

Do you have cruise control? Sometimes the diaphragm inside the cruise control hangs open allowing for vacuum to leak in, and around 1500-1700 RPM's the engine speed will be bouncy or you might here a small whine/whistle from the engine bay. If you're hearing whistles then you have a vacuum leak somewhere.

Before you do anything though scan for codes. Codes will point you in the right direction.

 

I didn't scan for codes 'cause the engine light wasn't on.

Guess what.The light came on Friday around lunch time.Took it to Advance & the guy said it was a bad TPS.

Thanks for the help!

I guess I should have waited a day or so & my XJ would have told me whats wrong with it.