I have a 85 740 wagon with 230000 miles on it. About 4 weeks

ago it developed a condition that required me to maintain at least 1500

RPM to keep engine running [Not fun at traffic lights].

If it stalled it would require a 10 second pause before re-starting.

The re-start slowly progressed getting slightly worse week to week

This was a static condition for about 3 weeks, which then progressed

to Choppy running at anything below 2000 RPM

I assumed the fuel filter was clogged, but began to test

the 740 loop for basics.

had spark

fuel pump running as it should

coil was OK, [swapped working]

Mass air sensor [swapped working]

Needless to say, i was perplexed. The Hall sensor was functioning

as the injectors were firing (injector test light is a great thing

to have, as it is a simple test which can rule out the

the hall sensor, cap and rotor, and usually the power stage.

Well I did the poor mans tune-up (new plugs wires etc)

and althought the car ran better, the problem still persisted.

Well 4 weeks after the problem surfaced, My car simply lost power

at 60 MPH and died. I had it towed (first time I have not been able

to revive volvo on the side of the road)

Upon getting it home, I checked and found Now I had no spark.

Well everything pointed towards ther power stage, on the

left fron fender [heat sinked 2 screws and a 6 conductor locking cable)

Sure enough replaced it and all of the trouble went awy, faster starting

and no stalling.

My point, The power stage mighgt take 1 or two months

to go into complete failure mode. It can trick you if

you are note carefull, as it tends to not fail all at once,

but in stages that result in poor performance.

Its a $90 part from volvo.

thanks to brickbooard Im back on the road.

Dave