All,
I've got a 258 with the Mopar MPFI kit, and have had this problem for quite some time. When idling after the engine warms up, the engine periodically "shudders" every second or two. It occurs even if I bump up the engine speed to a high idle, but eventually goes away at somewhere above what I'd consider highway speeds (I can get approximate RPMs tomorrow after I install my tach if it'll help). The symptom is nothing -too- serious, but it's something that should -not- be happening and I'm concerned it may be an indication of a more serious underlying problem. I've replaced (or borrowed for test purposes) the following parts recently:
- Fuel injectors
- Temperature sensor
- Ignition coil pickup
- Spark plugs & wires
- Distributor cap/rotor button
- CPU
- Speedometer pickup
Timing chain has about six degrees of slop. Any hints?
Thanks in advance.