After doing the whole clean/set the throttle body/TPS thing, changing the fuel pump relay, changing the radio supression relay, changing many of the vacuum hoses (all were original, 1991 vintage), testing the fuel pressure regulator both ways, testing the ignition coil resistance, and concluding that the problem that was causing lousy idling, poor power, hesitation, some surging idling, and some stalling was the failed (so I thought) in-tank fuel pump, I found out that the in-tank pump had not failed. And, I found this out completely by accident. So what was left to try? New plugs. I had put the last set in a long time ago, but she had a new head gasket installed by a mechanic this past July. Surely they would have put in new plugs, right? Nooooooo. You would not have believed the condition of what I pulled out.

Anyway, after all that, above, and ordering an in-tank pump which I was able to cancel, it was only $12 worth of spark plugs. Four new Bosch plugs and she runs like she is new again.

I never thought that worn plugs would make a car run so bad. Well, only my rotary engined RX-7, that thing eats plugs. 3000 miles, tops for a set of NGKs.
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Scott Cook - 1991 745T, 1985 RX-7 GSL-SE, 1986 Toyota Tercel (Don't laugh, it is reliable, faithful AND gets 41 mpg!)