Further research indicates it may be the Idle Air Control Valve acting up.
Will check it next.
(Let me try again. Data disappeared!)
As some of you may recall, original problem was a Code 42 that was finally tracked down to a faulty Ignition Control Module that had less than 4500 miles on it. Replaced the module The code 42 was removed and no other Codes have become apparent.
The new engine has new spark plugs m(just changed again.), plug wires, distributor and coil (Just changed again.). All sensors have less than 4500 miles on them.
The engine starts easily but idles very rough and can only be kept running by blipping the throttle; when first started. It frequently stalls when shifting from park to drive. You can hear the misfiring in the exhaust. No spitting back through the TBI. Once the engine reaches operating temperature, the engine still idles rough but doesn't stall as much. The engine seems to smooth out above 1600rpm. Transmission shifts normally once underway.
After installing the new Ignition Control Module, timing was adjusted as described in Chilton. "...disengage the timing connector which comes out of the harness conduit...This will put the system in the bypass mode."
After the timing was set, the Code 42 reappeared because the Direct Ignition System (bypass circuit) was "open", normal and expected. Reconnected the
"timing connector" and reset the Code 42. No other error codes have shown up.
Now comes the interesting part, with the "bypass circuit" open (disconnected) the ENGINE RUNS SMOOTHLY, with no stalling!
Reconnect the "timing connector", start the engine and the ENGINE RUNS ROUGH, misfiring, etc.
No error codes are being displayed.
What do I check next?
Your assistance/recommendations are much appreciated.
AK up North