nitty34

1993 4Runner. 3VZE. 260K miles

Dropped in a complete rebuild, and we're going nuts trying to figure this out:

First of all: not throwing any codes. Had 52 and 21, fixed both. Didn't affect this problem.

Engine performs fine as long as decent throttle applied. Acceleration is good. Power seems good. As long as I moderately 'floor' it, it climbs through the RPMs without incident.

If I accelerate slowly, or try to maintain a speed that calls for the RPMs to sit around 2200-2800, there is a severe 'dip' in the engine. Almost like it cuts out for a split second. RPMs dip to around 1000. Then it catches and I can accelerate back to original speed. Happens over and over and over. Always around this RPM range. If creeping at 1500 RPMs, won't ever happen. If on the highway at 3200 RPMs, won't ever happen.

Happens whether I'm driving or sitting still. Doesn't have to be in gear for this to occur.

Have replaced the TPS sensor and I'm getting all the correct readings from the new one.

Any ideas? I'm leaning next towards either MAF or distributor, but would appreciate some feedback before diving into either.

Thanks in advance for any help.

nitty34

Couple of other notes I forgot to mention:

Timing is holding steady at 10-12. Have probably checked it a dozen times throughout this whole ordeal.

TPS: When I unplug it the problem stops, but the engine runs in safe mode. Could it still be out of adjustment or a bad part (although readings are good)? Or is the safe mode preventing whatever is causing the problem to show itself?

Near Greensboro, NC - in case there are any experts close by who want to come help me solve this for a case of beer or a bottle of your choosing.

Again, thanks for any help.