Hey guys,
finally got my 01 3.5L montero sport running after an engine swap. But now I have low rpms at rest. I step on the gas and it accelerates just fine, but take your foot off the gas and the rpms go so low the motor acts like its going to die but it doesn't. any ideas?

 

how low is low? rpm's might be ok and something else causing the studderiing.

a little more info is needed

 

Is it the same with the A/C off? If that makes it better then check your Fast Idle Solenoid (I assume that model has one sitting right at the throttle body like my '99)

A possibly more likely problem is the Idle Air Controller. Did you also swap ECU's? If not, then the ECU has in its memory the settings based on your old engine's IAC. This also happens a lot when the battery is disconnected for some time as yours must have been. It takes a while for the ECU to reset the idle memory settings. Search for IAC or ldle Problems. There are lots of threads on this that will tell you how to resolve.

Finally, check the adjustment of your TPS (Throttle Position Sensor) This typically affects transmission shifting not idle but it could be worth a shot if the above don't help.

Ron

 

Under 500. Right above the "zero" line. the engine sounds like its going to die on me but doesn't

 

hey guys thanks for the help. what i ended up doing is taking off the air filter to expose to throttle body and just cleaned it out. it was pretty dirty. saw one of scotty kilmer videos on you tube to get an idea and it helped. but now i have to solve one last problem...... one of the spark plug boots isn't working. the one for the 3rd and 6th spark plug. gotta get that fixed

 

Im having problems with my car right now, is a Montero sport 1999, when I stop the car starts vibrating alot and sometimes turn off, can this be related to Idle Air controller?. I search the forums but can't find a thread to help me how to solve it or check my car to find out the solution.