2nd Gear Poster
Join Date: Apr 2005
Location: Sunny California
Stuttering at idle
Hi guys, it's been a while since I've had to seek MN12 expertise but, nevertheless, my car has developed a new issue. In short, like the title says, I've been getting a sort of stuttering after the car sits for a while with the engine at idle speeds. When it occurs there is a slight shudder/vibration and the tachometer bounces up and down about 50-100 RPM from idle. I first noticed it a couple days ago when sitting in a drive-thru and I was afraid the engine was going to stall. The stuttering stops with even slight throttle input, so things seem normal driving around. The car appears to start normally as well and I haven't gotten any CELs. I hooked up my code scanner to the car and did a KOEO test anyway just in case and it turned up nothing.
The last bit of maintenance I've done was an oil change almost two weeks ago. I replaced my O2 sensors almost two months ago to resolve a lean code. Prior to that it's been no more than regular oil changes and air filter cleaning for the past two years. I replaced the camshaft and crankshat position sensors early in 2009 (resolved CEL/code I had back then). Current MAF sensor is seven years old with about 45k miles on it. Current fuel filter is eight years old with about 50k miles on it. Spark plugs and cables were replaced about six years and 43k miles ago. The car itself of course is a 1994 model and has about 171,500 miles on it.
Any ideas? I fear something's wrong with the fuel system (dying pump?). I searched around the forums a bit and nothing obvious has jumped out at me. I'm kind of hoping it's something minor like bad gas but this issue started in the middle of my current tank as far as I can tell.
Thanks in advance.