TBI slow to return to idle
 

Hello everyone,

I have searched the forum and could not find the answer i need.

I have a 89 suburban, 5.7 TBI automatic. I have replaced every sensor (ACI, throttle position, egr, ETC.) and my truck still idles high and is slow to return to idle after removing it from gear or tapping the gas. It will return after 10 seconds but this makes forward to reverse a real pain. I have search for a vacuum leak with carb cleaner and starting fluid. It does not appear to have any leaks.

The truck does occasionally jump between 2nd and 3rd gear a few times if the throttle is just right when i accelerate very slowly. Makes me think I have a leak but can not find it.

The motor runs smooth as silk and starts instantly every time. When i was looking for burbs I noticed a few others running this way also but i thought they where in need of a sensor. Now that i bought one i realized maybe it is an issue with early model TBI???

Any help would be great,

Thanks
Jon

Re: TBI slow to return to idle
 

The first thing to do is check and make sure that the throttle is actually closing instantly when you let off the gas. Check for carbon buildup at the throttle plates and also open the throttle by hand to make sure it snaps back closed. It should not be slow,delayed or sticky.