I've been posting alot about my jeep running bad and thank you everyone for replies, I notice when I start it , it dont rev up like it use too then idle down, and when idling it would rev up and down on its own, could this cause my jeep to sputter and jerk when driving at highway speeds and lower.

 

really there are three possabilities here 1. vacuum leak 2.iac motor 3. tps there is a link on this site to test the later two the first is easy b12 chemtool and listen for the engine to rev.

 

Xj4life pretty much nailed it as far as irratic idle. Another consideration that causes irratic idle also is a poor ground to the IAC and/or TPS. I have an extra ground that is attached to a TPS bolt and the other end is attached to the firewall. It is just a 12 ga wire but helped when doing diagnostic checks with my multimeter, so I left it and it seems to have helped the idle too.