I have an 87 740 with 366K miles. Last year I had an electrical failure which caused car to stall and prevented car from starting. I replaced power stage and car would start but seemed our of timing and had no power. Took it to a non volvo shop and they replaced distributor, cap and rotor. Car ran fine but the tach would periodically bounce a few hundred rpms but did not seem the engine speed changed. This all happened in OH in Jan. When it warmed up the car would seem to miss as I went through 2500 rpms under load, but would run fine at higher and lower rpms. As the weather continued to get warmer the car would miss at any speed over 2500rpms after it warms up. The warmer the outside temp, the quicker the problems occur. Running the AC also speeds the problem. I have also replaced plugs, wires, coil and ign switch since this started. On fuel side both pumps, filter and FPR have been replaced (probably unrelated failure). This is a heat problem but I am not sure where to look. Any ideas on where I should look or what I could test??
Chuck