hello guys



Well its a 4.0 89 A/T. When in Drive and you put down the pedal it takes off fine...Also it drives fine when you give it good gas.


But if you give it like 5% throttle it almost like jumps and bogg's? As if its not getting enuff gas? But as long as i give it 25% throttle or more it drives fine, and aslong as i keep the foot on the gas its fine but as soon as i let off it almost starts cutting off? (fuel filter, tps? plugs)


Ideas?


thx guys

rob

 

Check for cracked broken vac hoses (Ive had to replace most).
Idle Air Control Motor (front face of the throttle body, motor side) about $65 Napa or dealer. You can pull it and give it a good spay with carb cleaner and toothbrush, dont get rammy with the little cone, don't pull on the cone. Carefull with the o ring. Sometimes a good cleaning works. When busted this reacts with very erratic idle speeds, stumble to 2000 rpm, very erratic.
Throttle Position Sensor - A suspect here but I don't know the facts on testing it definitively. Symptoms can be broad. Not sure about a clean up for it.

 

So I have the same problem but it happens after I go mudding and for me it would always be because I have water in my oil. I would simply put more oil in( I have a small leak so I don't have to drain the hole thing)

 

ok ill replace the idle air control motor next weekend ....i dont think i have a air leak in the vac hoes but ill check them all tomorow... i should prob swap the tps at same time.....

thx ill try it first day off...

 

Sometimes the IACM just needs the cone cleaned. Ive had to do both a cleaning and a replacement over the years. Maybe some more guidance will come in prior to the weekend.

 

lol ya thx man hopefully.....


ill give it a clean them tomorow save the 60 buks....

 

any other opinions?

 

I am dealing with kind of the same problem but mine dies when letting off the gas and coming to a stop. I watch the tach and it drops to around zero RPM's then back up to 500-700 RPM's. If i don't feather the throttle she will die at the light or stop sign or while letting of the gas to coast in traffic. The thing is it doesn't do it all the time which is why it is driving me nuts. I pulled the IAC and it was extreamly dirty, I cleaned and reinstalled, she idled better at start up but still dies when stopping

FYI...I bought the whole set of emmision vacuum lines through Summit Racing on ebay for about $40 with shipping.

 

I would look closely at the TPS. The idle air control motor does nothing once you step on the gas pedal. If it ran good at 5% throttle and stalled when taking your foot off the gas, then I would suspect the IAC motor.

 

Even though I cleaned the IAC it still might be bad? One thing I forgot to add is sometimes right after it stalls when I restart the idle is stuck high around 2300-2600 RPM's and will not drop until I shut it off for a few seconds. I tried to check the TPS but I did not know which connector to check because one goes to the transmission.

 

just cleaned mine (only the cone rod couldnt take off the throttle intake didnt have the damn bits) and its a bit better but still after the jeep gets hot as soon as i give it around 5%throttle or so it jumps up rpm a bit and down it will keep doing that untill i give it a lil more gas then it stops.....


next stop is tps check and maybee a fuel filter....Since the prev. owner has instaled a aftermarket intake system i noticed a few things.... the exaust return foil hose is not really conected to the filter so its not getting filtered air??? and also i did discover a vac line thats just floating??? when i plug it it starts killing the motor??? are all these things just stock air box plug ins?