RPM drops

TheRedZJ

TheRedZJ

Member
Joined
Feb 25, 2011
Location
Ayden, NC
i have a 95 zj with the 4.0 and when stoping, like when im almost to a complete stop my rpm's drop real low and shakes the whole truck, and sometimes when shifting into reverse or drive the rpm's will drop also. any ideas why this is happening? thanks for any responses in advanced
 
it aint throwing any codes out. its been doing it for awhile, hasnt got any worse. but the jeep idles at about 500-600 rpms and it will drop low, even sometimes to almost 0! but not cutt off
 
Just saw this 3 day ago in the shop on a ZJ. She came in with the same complaint and had the oem fuel filter still on it. I removed the filter and shot compressed air thru it, it shot out a jelly like substance. Installed a new filter and it ran great. I researched possible causes while it was in there. Low voltage and CCA's on the battery will do the same thing. The IAC "idle air control" will cause the same symtoms and not throw a code as well. Hope this was helpful.
 
cleaning the throttle body and iac usually takes care of any idling concerns on these things. sea foam spray works great, a good 10 second spray into the intake with the engine off, then let it soak while you clean the throttle body bore, throttle blade and iac. gonna smoke like crazy when you start it back up as it burns off all the carbon it loosened up. if it runs good under a load then the fuel filter is usually not the cause. could be due for one anyway though.
oh and the longer you let the sea foam set in the intake the better it works. just be careful not to spray so much that it hydrolocks the engine.
 
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