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[WabbaStang]

OK, been trying to diagnose this thing and every idea ends up with more questions.. HeLP!

Idle is slightly rough, like a miss. If you slowly ramp up the RPMs (in neutral, drive, whatever), the vibration gets more and more pronounced. When you get to about 1100 or so (where the shake is the worst), RPM suddenly jumps to about 1400, then ramps up fine again and smooths out above 2000 or so. Same thing when you slowly back off, hit 1400rpm and then drops right to 1100 and wont hold in the middle. It's near impossible to get it to hold between 11-1400, if it will do it at all. This is where the vibration is horrible, shakes the whole truck. We kept thinking it was a t/c problem because when it hit lockup it shook like hell, but with more thought and playing with engine speed I think it's because right when it hits lockup at an easy cruise, it lands the motor right at that RPM range where its the worst. After it hits O/D and drops to ~1300rpm, shakes like crazy and gets worse when you give it throttle. If you ease it on and get it closer to 2000, it smooths out. So doesn't seem to matter if its in neutral or any gear, does it all the time, just really pronounces it under load.

No codes/SES light either!

Also noticed that once in a while it will do the same thing from about 700-1000 RPM, if you ease the gas slowly off it won't hold within that rpm range.

Replaced UVC wiring last night, slightly smoother idle but no real change in symptoms. [img]/ubbthreads/images/graemlins/shrug.gif[/img] [img]/ubbthreads/images/graemlins/shrug.gif[/img] ARGH!!!