When I am decelerating downhill sometimes the engine rpm's will just drop to around 800 even though still traveling rather fast, and make terrible noise. I have to "stab" the gas pedal and it comes back to normal. this is not a safe thing to have to do especially if travelling down a mountain pass.
This is now starting to happen more often, even on flat roads , but still only when I have let off the gas pedal for a bit. When I replaced the serpentine belt recently, it went away for a short period of time - maybe a week or so, then started again. Any ideas?
Sounds like the trans is getting weak.
Check the trans fluid level.
That sounds like the transmission is going into neutral as your coasting, do you have a check engine light on? As this is a computer controlled tranny there could be a sensor misread or a bad solenoid inside the transmission. The only thing I can think of when it worked for that week is maybe you disconnected the battery to do the belt work, if not it was just coincidence that it work for that week.
Thanks for the response's - When the RPM's drop, it is lower than the normal idling RPM and there is a corresponding noise (load whining noise) , maybe pulley slipping?
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