I posted earlier and I wanted to return with an update. I have a '90 240 DL. Complained of the above and low compression. First mechanic wanted to do a valve job and said that would be just the start!!!! My lesson - always get a second opinion. Took it to another volvo mechanic in the Fraser valley where I am in. Turns out although low compression is one problem it isn't THE problem. They replaced the O2 sensor (DARN! I had that replaced in January but the mechanic then cut into the lead wire rather than replacing it and that caused pronblems) and cleaned the flame trap. This is probably what was causing the bulk of the problem. Idle is smooth and acceleratioon decent now plus they washed the car and cleaned up a seperate problem no charge. THEY are now my mechanic. Still need to look at replacing the air mass sensor and possibly a gasket in the exhaust manifold. Are these parts difficult to replace? Thanks everyone for their previous advice.