I noticed that my RPM gauge surges back and forth if going downhill, with it my foot off the gas pedal. The feel is like it s clogged or something, but if I return my foot to the gas pedal all is fine. Seems like it happens around 2000 RPM's.

Has anyone else had this problem? What could it be?

 

How much does it fluctuate 200-300 rpms? When was the last time IACV was cleaned?

 

Yep, 200-300 rpm's is about right. Cleaned IACV about 3 months ago.

 

Wish I could narrow it down for you but it sounds like an air (vacuum) issue. Not 100% sure. Especially only on downhill travel. Wait... Have you checked your resistance of your tps? If it were me I would start with checking essentials air,fuel & spark. Yes you are getting all three to drive, but one of the three is not performaning correctly. Find which one and narrow it down to the area. I only mentioned the tps bcuz I remember when that starts to go one gets all types of crazy response from the throttle. Sorry if I send you on a wild goose chase. Just trying to assist in giving you some direction.

 

Is it an auto and manual trans?

 

Idk why I assumed it was a 5spd.

 

Auto it is.

 

That changes everything. It could be something as simple as the tcu on the autotragic.

 

I don't think you have a problem...it sounds like the trans is driving the engine, or more like down shifting into a lower gear in deceleration mode and your loading the engine up instead of the brakes.....If you have any ignition misses they will be felt or even header sputter you will feel it a little.....One other it could is you torque converter stator blades sticking instead of freewheeling be that would be felt during all decelerations not just downhill decels! Put your foot and the accelerator and the problem goes away you have no problem......this is similar to the question about brake creep and the sound it makes when seating @ a redlight and you lighten the brake pedal pressure with your foot a little and you hear the grinding or rubbing like noise....Ain't nothng wrong!

 

It waas my distributor. I replaced it. No more surging back and forth downhill.