'93 940 Turbo B230FT, 188K miles.

In the past 4 months, I had 3 or 4 crank-no-starts (even in cooler weather). Each time, I’d let the car sit for 10 minutes and it would start and run normally afterwards.

4 weeks ago, the last crank-no-start left me stranded. After the car sat overnight, it still didn’t start. I had my wife crank it as I reached under and tapped on the main fuel pump with a tire iron. The car started! This happened again a couple days later and I got it started by tapping on the pump again. I replaced the main fuel pump and fuel filter and I haven’t had anymore crank-no-starts.

This car has been acting up in other ways for the last 6 weeks, since outside temperatures are warmer. Conditions are worse and car acts up with greater frequency when ambient temperatures are above 80 degrees.

When accelerating with anything more than 1/2 throttle (merging on highway, or going up a hill, apprx. 3200 RPMs), engine will bog down and lose power. If I'm not careful and back off of the throttle, I will hear the engine ping. Above 85 degrees outside, engine will hesitate and ping more readily at lower RPMs and even 1/4 throttle. I must take off from stop lights pretty gently to avoid the ping. Increasing the load on the engine by running the A/C and carrying more weight causes more frequent losses of power and pinging.

Occasionally, the car does not want to idle after it is restarted when hot. I can be out running errands, have the car off for anywhere between 10 to 45 mins., crank it and it will die right away. I have to hold the gas pedal at 2000 RPMs for 30 seconds and then the car will idle on its own. After this happens, the idle typically surges (between 800-1200 RPMs) for as long as 5 mins. (car never dies).

Last week I brought the car to a reputable Volvo-only shop. They tested the fuel pressure for main and in-tank pumps (perfect), ignition timing (correct), looked everything over, and test drove the car. Unfortunately, it was a cooler day and the car sat overnight at their shop, so they were not able to duplicate the problems that only occur when the car is hot and it’s hot outside. At the time, the Check Engine Light was not on and the OBD did not store any codes.

The Check Engine Light finally came on a few days ago on a 90 degree day. OBD code 1-1-3 Lean misfire.

New parts in last 5,000 miles:
- main fuel pump and fuel filter
- cap, rotor, plugs (NGK copper)
- idle air control valve
- oxygen sensor
- vacuum lines
- cleaned flametrap
- cleaned MAF
- cleaned throttle body
- 93 octane Shell gas
- compression test: 150-145-145-145

When engine is cold or it is below 72 degrees outside, there is no hesitation or knock and it runs normal.

Oh great wizards, what do you think?
Chris