This jeep has ran funny for years ive replaced alot of stuff now im getting pissed i cant seem to nail it. I replaced many parts. Today i just installed the other sensor ive waited 6 months to buy the new iac motor and nothing still pretty much runs the same idle is real low it starts at about a grand then 40 seconds later drops down to the line above the zero. I see a line before the 1000 mark and a line above the zero mark the needle is between those 2 marks at idle slightly bouncing some times more then others . So far ive spent a few hundred on sensors. The only thing i seem to notice today is when i put the car in reverse and go to give it gas it dont bogg out like its going to stall when i touch the petal. Before i would have 2 step on it for it to backup and not die seems like i can just touch it now. However when in park it idles like as before my idle will go low motor will sound rough then comeback When i tap the gas at idle sounds like its bogging/choking and gonna die unless i let off the petal then it comes back or if i step on it then it straightens out. I almost think its a fuel problem. Keep in mind ive replaced plugs wires fuel filter changed the oil put a new vaccum harness in took the pcv hose that was going into the top of the motor and cleaned it all out got all the carbon out of it replaced the oil filter air filter new tps sensor took out the throttle body and cleaned it real good idk what is going on im stumped. One guy has told me i should fix my exhaust leak but i dont see that making my jeep magicaly running perfect the guy claims all jeeps are known to idle funny and now says its my o2 sensor right along. The guy never told me nothing about that when i asked he just said try fixing my exhaust leak i was originaly thinking about the o2 sensor being bad now im hundreds of dollars into this i dont want to waste anymore extra money. Buy the time im done ill have the whole motor rebuilt. Any ideas?? Not once have i seen an idiot light come on i dont understand fully how a car could run like this and not a single check engine light.

 

Not sure if the 89 had this but i had the same problem.and finally found out it was my map sensor. Check that. Also check ur.grounds.

 

Im not a complete genius by far and Im having some idle problems myself, but indulge me...have you checked the crankshaft position sensor? just a thought.

 

That too

 

I have given that a thought as ive herd that could be my cause of a hard start as well ill look into it Keep in mind i have low miles only have about 90 thou miles on this jeep

 

I'm going through a similar issue with mine. You should definitely check the fuel pressure. 31 psi normal and 38 psi with the vacuum line disconnected. I've read a ton here and a lot of people find out their fuel pressure isn't where it should be. Autozone rents a really nice kit that is super easy to use, you just got to plop down about 160 for it but you will get it back. My next move will be switching out the injectors.

 

im gonna try some injector cleaner with a new tank of gas incase they are somewhat dirty. and i think the fuel seems more like it in a way because my jeep does crank after about 10 seconds over so its not like my jeep dont crank or fire at all so i cant imagine the cps being bad my uncle had the distributer apart before he could have had it replaced but if i recall its just a grommet that i would need as my jeep still turns over. Basicaly the problem is still the same as it has been for 10-15 years if i were to disconnect the pcv vaccum line e.g pull it half way out like the guy had it it would idle just higher enough to run smooth and be at 800 or 900 rpm. Im trying to avoid that i want all vaccum lines fully connected no vaccum leaks so idk i guess im gonna be looking at fuel pressure and still trying to find the cps usaully its located on the front of the motor no??? Ive also checked the map sensor at the b terminal it was at 4.89v in the acceptable range so its getting juice doesnt tell me if its working

 

ok i had the same problem earlier this month on my 89 chrokee... it was the tps(throtle position senseor). there is a way to adjust this but for the 12.00 part i say go to autozone and get a new one. it is really easy to change. 2 screws...... like i said i hope this wors for you. i have a much bigger problem.... i have no fire going to the distributor.... the jeep cranks over strong, getting gas , just no fire......it started the other day and put it into revese and it shut off on me after moving 12 inches in reverse.....i am stumped. do not know whereor what to check.......

 

you lost me and did u not see the tps is brand new ive spoke about it

 

Try checking the coil there should be one if not its prolly the cps is bad or its just wires that are bad on one of those connections. Even still 10 to one says what im saying wont work and it will still not run and you will be out another 100 or 2 like i am i guess thats how it is