My 1988 240GL, 120K, began starting and running as if one cylinder was missing. I installed new plugs, high tension wires, dist. cap and rotor, and a different air mass meter. It got better, but... Yesterday during state emission check, which requires checking tailpipe emissions 90 seconds at idle and 90 seconds at 2500 rpm, it still was missing on sort of a random basis, obvious even at 2500. (BTW it passed the test, to surprise of the test guy) Now I'm deciding what to do next besides throwing in the towel and taking it to my Volvo tech ($70 per hour). I think it must be the fuel system somewhere, your suggestions will be greatly appreciated. Bob

on my '93 245 the timing belt was off a tooth. same symptoms. the previous owner must of drove it that way for 5 years?

BC,

If you problem is in the fuel system at one of the injectors I think that a mechanic's stethescope on that particular injector would give you an indication.

This is a new gadget to me. I have used a 3-foot length of 1/2" black polyethelene pipe to hear closer to things, like alternator or A/C clutch bearings. I'll try the pipe, what should I listen for? Thanks, Bob

A mechanic's stethoscope is safer to use than a pipe or a rod (although I've used both). If you have a Harbor Freight or a good auto parts store nearby, you can get one at low cost. I think mine was less than $5.00US. You will be surprised at how much you can hear going on in your engine.

Check the fuel pressure regulator.

After having rough cold run problems with my 84 240 - it turned out to be the fuel pressure regulator. This is after the following - plugs, cap, rotor, wires, coolant temp sensor and AMM swap.

OK, I'll check the FPR. If I find it, and test it, and it is bad, has anyone repaired one? Thanks, Bob