Started my car this morning and the tach went to about 1500 like it always does then dropped to about 500 and lumped around there. This made me nervous so I touched the gas a little and it almost died. Then I didn't want to hurt anything so I shut it off.

Ignition: I just replaced the spark plugs with new NGKs but I didn't check the gap before they went in.

Fuel: all pumps and injectors seem to be working. The FPR is new and does not leak.

Other: What about the IAC? I don't know how to diagnose this. What about a dirty TB or my TPS slipped?

Thanks in advance.
plan for today: read FAQ, go out and try stuff.

--Aubrey
'89 745GLE 16v

Could be a number of things- the usual disclaimer- check the tps switch and connector at the throttle body, had mine disconnect and exactly those symtoms another culprit may be the dreaded radio relay mine went shortly after the tps so it may be hard to say which came first

up top, under the features menu, choose 700/900FAQ and go to the performance section.
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Ken
1990 Volvo 740 base sedan (B230F)
My Volvo 'Project'

well I regaped the plugs, cleaned the TB and the flame trap. still idles like crap: Starts right up, revs to ~1800, drops to ~1000, smooths out for 4-5 sec., drops to ~500-750, lumps, bucks, shakes, and threatens to die.

Now I'm thinking IAC. How do I clean, test, rebuild it?

--Aubrey

Your symptoms do match the IAC as a possible cause. Here's the FAQ link to the IAC.

http://www.brickboard.com/FAQ/700-900/EnginePerformanceSymptoms.htm#Cold_Start_Dies_Dirty_IAC
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dnvolvo '89 765T 200K - '91 245 100K