I have a 2004 Nissan Frontier Xe, 2.4 liter, manual transmission. It has roughly 123,000 miles. About 6 months ago, I cleaned the throttle body like in Scotty's video but ever since then, anytime the truck is rolling (either with the clutch pressed or in neutral), the RPM's shoot up to about 1500 (sometimes up to 2000 during the colder weather months) and it doesn't come back down until I come to a stop. Otherwise, it idles totally normal. It only happens when the truck is rolling. I have replaced the MAF sensor and intake temperature sensor. I have had 3 mechanics look at it and all have done smoke tests to test for a vacuum leak. None of the mechanics could figure out the cause or solution to the issue. It doesn't seem to do it as much in hot weather but it is still apparent when the AC is blowing. I have also tried unplugging the battery to reset the computer but the problem still persisted. There are no codes. Any ideas??
You might damage the butterfly valve in throttle body assembly.
You might try the relearn procedure and pray it helps:
Thank you for the response! From my understanding, the throttle body is cable driven, not electronic. I think it was the last model year that they made it like that. So the idle relearn doesn't work, or at least it didn't when I tried it a few dozen times :/
If the butterfly valve has been damaged, it would probably mean I need a new throttle body... correct?
Yes.
Check for proper function of the temperature sensor. It may be giving a bad signal to the ECU. It's 18 years old.
Thank you for the response! Are you referring to the air intake temperature sensor? I've already replaced it but it wasn't OEM so that could be an issue. I'll look into it further.
It's always good to use OEM for sensors. I was talking about the coolant temperature sensor. The one you can't really get to without removing the entire intake system. Admittedly, the coolant sensor is a long shot. I would also do a deep scan for any stored codes.