I'm trying to resurect my old mothballed 740 (and fix the problems that stopped me from driving it 4 years ago).

1986 740 Volvo GLE Wagon. 230,000k (the last 70,000 are mine) Automatic Transmission, non-turbo. Timing belt replaced at 200,000 (after it broke), Fuel pressure regulator replaced at 220,000. Tuned regularly (until I stopped driving it in Dec 2000). New plug wires today (helps) The car has been started regularly, although not driven much, or more than a few hundred feet in the last four years.

The car has a variety of general problems (some minor damaged bodywork, steering rack is loose, needs some new brakes, etc). These are within my skills to fix. However, there are some nagging engine issues that I'm looking for help in diagnosing. I got the car started up today and back to running "normal" (that is, back to presenting it's old symptoms).

Old/new issues (I think they are all interrelated).
1) The car will always start right up (a sign the cold start works well, eh?)
However, it kinda "chugs" and the idle with fluctuate between 500 and 900 RPMs for quite a while before stabilizing at about 700 rpm. It takes "forever" to warm up (on the dash sensor), when it finally warms it purrs like a kitten. However, it will frequently die shortly after starting, usually on the low end of fluctuating. It will always start right back up. When I try to rev it (to get it past the rough parts) there will frequently be a one of two second delay between pressing the pedal, and the engine reving. Usually pressing the pedal will kill the car before it has the chance to rev up.

I suspect this could be the temp sensors (I hope not the one in the header), and/or the Throttle Body. I did a quick cleaning today (but didn't remove the TB). Also checked the vacuum hoses and the bellows between the AAM and TB (they "look" okay). When at normal temp, I removed the connector to the AAM while running and the car continued to idle well (AAM is fine?). Oddly, I removed the vacuum hose to the FPR and it idled a marginally smoother (??) (relatively brand new part).

2) If I drive it when cold, it lacks power (but doesn't stall). The car will often give me a misfire/backfire or two, then I get a surge of power and normal operation. This confounded my mechanic and he never solved it.

3) The car has always failed it's emissions test with excessive CO. This is one of the reasons I mothballed it and bought my 1990 740.

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Even when at normal operating temp, the car still isn't running quite perfectly. I can feel vibration (lifters need adjustment?, a cylinder not firing?) and a regular "puffing" noise from my tailpipe.

After reading the brickboard maintenance FAQs, I strongly suspect that varnish deposits on my TB and some mis-adjustment/slipage/worn out in the TB plate may be the cause of several of these problems. I curious if these symptom suggest anything else is going on?










The last couple of times I