'89 245 w. 424k km , 5 speed

I started the wagon at work, drove about 3 blocks, and parked. About 10 minutes later, it stalled out badly on starting. Idle was very erratic, had to keep feathering the gas. Drove home (about 50 km, 30 miles), ran better at highway speeds, but still seemed to bog when shifting, didn't accelerate normally. Idle would vary from about stalling to 2k. Check Engine light came on, but I didn't retrieve the codes, and wiped them with the battery off later.

Done so far: Checked the TPS - it ohms out correctly (to both sides, Idle and WOT), but does not "click" as loudly as other TPS's I've seen. Replaced the IAC (feeds back into snorkel) with known good used unit (no change, and resistance of both units was the same), checked for obvious sensor wiring problems, replaced ignition rotor with better (less worn) used rotor, checked top of snorkel for extra holes - temporarily taped over one possible tiny hole rubbed by vacuum line. Ignition cap is worn, but has no gross visible faults (ie. broken off terminal).

Just before cleaning the throttle body tonight, I decided to check the AMM. I disconnected the battery, waited a few minutes, and disconnected the AMM. I then reconnected the battery, and started the car. BIG difference !!! The car would now idle pretty near normally, about 800 rpm. Shift light was flashing rapidly, I let it idle for 2 or 3 minutes - idled fine. Bogged if the throttle was applied, but I kind of expected that. Disconnected the battery, reconnected the AMM, tried restarting (in case my new/old rotor had been the cure). Car was back to really messed up idle.

>>>>>>I am going to cruise thru AMM postings, but wanted to ask here - is this typical of a failed AMM ? <<<<<<<<<<<<<<<

I am familiar with dirty throttle body symptoms, on this car it will stall once, typically after a high speed highway run in very cold Canuck weather - always restarts and idles fine - problem disappears after cleaning the throttle body, AND never affects anything above idle. The throttle body was really dirty when I first got the car (90k), it would idle smooth, but only at about 600 rpm.

I do plan to clean the throttle body, and put on a new cap/rotor, and silicone the snorkel, but want to get this large scale problem isolated before I clean up the tune-up items. (AND, I prefer to get the car running normally, BEFORE I start servicing ignition cables....).

Rgds, Dave.