OK folks. After two attempts (July 3 and July 30)and no reponses - I'll try one more time. Wake up fellow brickboarders and share your experiences, please!

On my 96 850 Turbo 96K, for several months I have been getting various misfire codes (P0301, P1310, and a cylinder 2 misfire code - lost the actual number)and one knock sensor error code (P0326). When cleared the codes don't come back immediately, but apparently can be re-induced under hard acceleration. Of course, the CE light accompanies the codes.

At all times there is a random occasional miss at idle. For example, while waiting at a stop light, there might be no misses - maybe one, then at the next light there may be 4 or 5 misses. These misses do not seem to activate the error codes. FI cleaner added to the gas has not helped

At hard acceleration, when approaching 4,000 RPM the engine begins to run rough, stumble, hesitate, lose power, etc. - any of those desciptions will do. This behavior does seem to activate the error codes.

The local Volvo dealer replaced the plug wires, coil wire, distributer and rotor, and a FI relay to no effect. An ind shop then looked at it and said they were "stumped". They didn't think it was FI, but said all they could do was start replacing things and see what worked (forget that!)Also see post by chrisq dated July 20 "had a CHECK ENGINE LIGHT lit once and replaced TONS of PARTS" to see that this strategy did not solve chrisq's similar problem.

I wondered if a clogged fuel filter, failing fuel pump, or bad coil could be the cause. Then I found a June 30 post by bpjalaie. This post indicates that a failing hydraulic tensioner caused a timing belt to "slip" a few teeth on one of the "gears". Fixing this apparently fixed a random misfire problem that sounds similar to mine. Can a timing belt be "a little bit out of adjustment" and would that logically cause my symptoms but not worse ones?

So, though the car SEEMS to run OK between idle and 4,000 RPMs, could my symptoms be caused by a timing belt becoming maladjusted????? What do you think is causing this frustrating and mysterious problem????? Any suggestions on troubleshooting any further (without just starting to replace parts - I can't afford to do that much less pay a shop to do that)?

I would appreciate any and all input as I am about the the point of givng up!

Regards,

Calvin
92 940 197K
96 850 Turbo 96K