soulscapex

Hello all, my 98 jeep GC is having some weird issues with the rpms, when i start it the rpms climb till i step on the gas, which usually corrects them, it seems to do it when i put it in park , a few times it went to bog out when coming to a stop. Some days it runs fine , and after a trip to the store and back when i restart it they will seem fine , it will usually climb to about 3k in park if i dont touch the gas a few times. What could be causing this.

Titan Greer

Considering nobody has replied to this issue hopefully it has been fixed. Could be multiple issues, need more detail. After idling at high rpms, when you give it throttle and it corrects does it shudder/ try to die? Do rpms stick at certain speeds or shudder at certain speeds? From limited detail I would say it's electrical, probably a sensor. My 97 cherokee would idle high rpms, then when given throttle would shudder and try to quit, as well as die at stoplights. If it is rpm dependant like mine, I would take a look at the tps (throttle position sensor) really quick to check, underneath the intake on top right side of carb. Literally 3 bolts. Swapped mine out 3 weeks ago. It had a broken pin that regulates the throttle on carb causing it to shudder and die.

soulscapex

No i didnt get it fixed yet , weather has been to crappy , but i already changed the TPS a month or more ago, I was doing research and saw some info about IAC is bad or dirty , and to answer the questions no it does shudder or die when giving it gas in park. No when i have to stop at a light or behind someone suddenly , it will drop all the way down almost to stall. for the most part it doesnt do it while driving , it only really acts up when in Park.

Hatsuwr

If you feel like testing the TPS to be sure, just check the voltage between its center terminal and ground (engine can be off). With the throttle closed it should be a bit over .2v, it should gradually increase to a bit under 4.8v when fully open.

IAC sounds possible too. Wouldn't hurt to clean it either way. Not sure how to test it. I believe there should be a small resistance between the inner two terminals, and a small, but different, resistance between the outer two coils. Also, if you have the IAC removed from the throttle body but connected electrically, when you turn the key to just before starting, it should push the pintle outward. Doesn't necessarily tell you anything if it doesn't move, but if it does move it makes that unlikely to be the problem.


May as well take the whole throttle body off and clean everything.
Throttle body bolts tighten to 108"lbs
Sensors are each held on by 2 T20 ( I think it was T20...) screws. IAC and TPS tighten to 60"lbs, MAP sensor to 25"lbs.