For the past year or so I've had some annoying RPM issues. I can be heading down the freeway (though I don't have to be on the freeway for this to happen) and push in the clutch to coast, and the RPMs will drop as expected. When they hit 1000-1500 RPM they bounce up to 1500-2000 RPM, sit there, then sink down to idle.
Here are a number of things I have done to remedy this. New plugs & wires(Bosch platinums - will bee replacing with NGKs this summer), distributor car (no rotor), fuel filter, cleaned intake from MAF to TB including sensor on TOP of TB. I have had the car for almost 2 years and have not changed out the distributor rotor. I have deemed it impossible. I even had a mechanic friend come over and try and get it off, but he couldn't either. We suspect the possibility that someone glued it on. (if you knew much of the history of this car and how poorly it was taken care of before I got it, you'd agree also). I have cleaned out from behind the rotor assembly as good as I can with some intake cleaner. I just sprayed it in there.
Well after doing all that cleaning today, I honestly can say that I "feel" a little more power from the motor. The engine is much more responsive than it was. And that is in addition to the new A/C compressor I put in this weekend with it running. I can even feel the VTC kicking in. It used to be I couldn't feel it kick in. It was always "smooth" power with SLIGHT surges. Atleast that is my guess for what that is. So while I am happy that the engine performance has improved, I'm still irritated about the RPMs acting like that. Anyone got an idea?
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Donovan Maxwell
2002 Altima 3.5 SE - Wife's Daily Driver
1984 300ZX NA -Project Car
1993 Mustang LX, 5.0L - Daily Driver
Mine does that too - put the clutch in, it will drop to ~1000, bounce up 1500, then settle to idle ~800. Never have figured it out, and I bought the car off of someone I knew, so I know that it was meticulously maintained. Additionally, it only has ~50,000 miles on it (1992!), so I'm not sure what wouldve gone on it to cause this.
Off more concern, is that on some cold mornings, RPM's would bounce between 1500 and 2000, after it had been running for a while and already warmed up. Seemed like this started happening after I did the WAI. Weird. It happened probably 3x - bounce around for 10 seconds and then settle to normal idle again.
Final note - I've never seen a car with such an agressive warm up idle profile. When very cold (i.e.: -30), it would idle at ~2500 - enough to start in 2nd without touching the gas - crazy! Anyway, car's of the road for future winters (86 Samurai winter truck), so I'm not worrying about it.
Well,
If your low RPM's are really acting up, check your vaccuum hoses and make sure all of your engine sensor grounds are good. Idle surge is hoses, slowing down surge is grounding.
Thats to my knowledge anyway.
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