1. My tach sort of has a slight twitch to it at idle. Nothing big at all, you can just notice it while looking at it. What could cause that?

2. If I rev. my motor then the tach goes up but then when i let off it drops down to right above 1000 rpm's for a moment and then drops down to normal idle (700-800 rmp's). It is almost like it "hangs" there for just a second. This is not just after cold start, it is all the time.

3. Has anyone ever used Seafoam in their cherokee? I hear it makes a nice difference in most vehicles. Anyone recommend it from personal experience?

 

Not sure about 2 but the first problem i have to i tried chasing it and no luck its just the tach it self ive narrowed i down to and ive used sea foam and have had good results from it

 

Did you do the seafoam in the crank and gas?

Also, the second problem seems like maybe the throttle is hanging for a second before dropping to idle. I dunno if the throttle lever spring can hang it or its in the throttle cable or the intake or what.

 

Not sure about the throttle hang but i poured it slowly into the intake and after putting it in i shut it off for about 12 minutes started it back up and if it smokes alot then thats how you know your engine had gunk in if theres a little bit to no smoke your engine is clean

 

cleaned my iac today and it helped a lot with the rough idle and the bouncing tach.