Ok, I've had an idleing problem for some time now that I addressed a while ago. Now I have a little more info on this phantom problem. It only does it when the motor is cold. As the idle progressively drops everything is fine and smooth until, I hit 1200 rpms. Then BAM!! Major stumbling and shaking! As soon as the rpms hit 1000 it's smooth as glass. Then when it's warm, the rpms rest at 700. It's just that when it hits 1200 it is insane how much this thing stumbles! The car definitely threatens to stall, but never has. And it's been doing this for 2 months. Also it doesn't do it all the time. I figure if it is something mechanical it would do it all the time, and in more places than just 1200? I'm thinking something with the ECU?? Again, no fluid leaks at all, oil is great, no weird noises, no performance losses whatsoever, and no weird smells. Totally confused here. Maybe this info helps at all? https://www.nopistons.com/forums/pub...1047683561.gif

well first off...... cold startups with our cars usually are always shakey,



when was the last time you replaced your plug wires? maybe its time for an upgrade, startups are usually rich, and you're shaking cuz your spark isnt good enough........ i might be wrong too

That's what I am hoping on, I just got my downpipe from Pettit, and plug wires are next. I did change the plugs to NGK Iridium "Laser" plugs (whatever that means) about 6 weeks ago, and 3 of em were black as night, and the 4th was half black and half beige, really weird too I mean the color was seperated straight down the center of the plug? But yeah, wires are next, as soon as the downpipe goes on.

when the car is warm, try slowly reving it up to that 1200 mark. If it allways happens at 1200 it may be your TPS. it could have a "dead spot"

That could be, because sometimes when it's warm and I'm idling at 700 rpms, out of nowhere the rpms will start to bounce up to 1000 then back to 700 and it will repeat this for like 2 minutes then stop. It's a real erratic thing and rarely happens, but has definitely done that a couple of times, which made me think of a TPS. I wasn't too worried about it, I was mostly concerned with the 1200 rpm stumble thing, but you may be onto something.