Intermittent Miss/Idles Rough
Thread Starter
Le Mans Master
Joined: Mar 2006
Posts: 5,262
Likes: 0
From: E. Amherst NY
Intermittent Miss/Idles Rough
Been fighting this problem with my '86 'vert for the last few weeks. Here's what I've done.
New Plug Wires
Checked Injector Pulse
Cleaned IAC & Throttle body
Adjusted TPS
Checked timing
Checked injector connections
Run injector/fuel system cleaner through it
And I'm sure theres a few other things I'm forgetting.
Anyway, the idle stays around 600-700RPMs, so its really not moving around much. But, its not a very smooth idle, it sounds like its missing at random intervals. When driving around, and the RPMs are low (1000-1200), with very little to no throttle application, the car has a stutter/bucking sensation. Put your foot into it, and its gone immediately. When it does it while moving, its almost like there's occasional slop in the drivetrain.
My next steps are probably to pull plugs, replace cap, rotor & plugs.
New Plug Wires
Checked Injector Pulse
Cleaned IAC & Throttle body
Adjusted TPS
Checked timing
Checked injector connections
Run injector/fuel system cleaner through it
And I'm sure theres a few other things I'm forgetting.
Anyway, the idle stays around 600-700RPMs, so its really not moving around much. But, its not a very smooth idle, it sounds like its missing at random intervals. When driving around, and the RPMs are low (1000-1200), with very little to no throttle application, the car has a stutter/bucking sensation. Put your foot into it, and its gone immediately. When it does it while moving, its almost like there's occasional slop in the drivetrain.
My next steps are probably to pull plugs, replace cap, rotor & plugs.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Tonight when its dark, defeat the underhood lights and with the engine idling, look for sparks along each spark plug wire. There aren't supposed to be any. Replace any wire looms that are damaged or missing, they keep plug wires from touching metal (ground). Plug wires have microscopic pin holes and will spark through these pin holes to ground if ground is touching the wires. New or not, measure the resistance of each plug wire, they should be about 5000 ohms per foot. Very high resistance shows a defective plug wire. I had one on a 2 day old set of new plug wires.
