My '87 240 has been having a few problems intermittently for the last four or five years. Occasionally the top end power on the highway varies--you can tell the power level is down, since car just won't pull as strong or run as fast.

Also, sometimes it sputters, bucks and pops under acceleration (25-30 mph) for the first minute or two after a cold start.

Also, three or four times a year, the car won't start. Even though it's been running fine for months, you go out one day and it just won't start. Cranks strong, but it either won't try to catch or just barely catches. Two ways to solve this. 1) If you just let it sit a day or two, it will sometimes then start. 2) If you crank long enough, and flutter the throttle, it will eventually catch enough that you can keep it going with more throttle flutter. Once it really catches, then it's fine for another couple of months.

Have replaced both fuel pumps (and checked hoses in the in-tank unit), fuel pump relay, fuel filter, fuel pressure regulator, temp sensor, distributor rotor and cap, coil, and have cleaned throttle body and changed out ECU and AMM for known good units.

However the problem still persists. I'm wondering if this is may be a bad throttle position switch, especially given the effect of throttle fluttering?
(One thing--the switch does "click" as it's supposed to when you move the throttle off idle with the engine off).

Any help appreciated!

Dave S.