i think noise1 could be flex-plate knock even if tightened completely, it could be cracked around the holes. something to consider.

 

I dont think the engine is revving up, instead I believe it is stalling for a split second and picking itself back up. The tack jumping up could be caused by the crank sensor reading being bad.

What I am saying is to look into your crank sensor being either dirty or, faulty. Could even be wiring.

This was caused by my O2 sensor wire rubbing on my driveshaft.

 

Well I did just recently replace my CPS... There's a chance it could be bad. I did clean the area before putting the new one back in.

 

After cleaning my IAC... Was finally able to put some drive time on the XJ.

The jump in RPM's is still an issue.

Should I look to testing my CPS, or perhaps focus on the TPS?

Not throwing me any codes either.

 

Anyone???

 

little late but man try replacing the TPS, my jeep had same issue ive gone through three of these things off roading