So, after doing boat loads of troubleshooting to fix poor idle & poor acceleration under load, a local shop found the problem. See all that's been done over the last 2 months:

new plugs, cap & rotor, plug wires
new fuel press regulator
new fuel filter & pressure checked by Volvo shop
cleaned throttle body & new gasket
checked idle air control motor
New O2 sensor in the exhaust line
removed the injectors & had them tested & cleaned at Dr. Injector (specialty shop in Seattle)
new filter sock on tank fuel pump
removed CAT & checked for loose stuff - all ok
all of the Bentley section 241 electrical checks are OK
Timing, idle & mixture set by Volvo shop
checked for vacuum leaks (removed the accordian hose to thoroughly check it)

Last Friday a different Volvo shop (All Volvo in Seattle) could not get CO mixture set (also see additional post: http://www.brickboard.com/RWD/index.htm?id=1104262) Turns out the fuel injectors were bad. They then tried a set of used injectors, set the CO mixture and I can't believe the difference. I actually have acceleration.

So here is a follow up question...

Does the grade of gasoling used, and source make that much difference? I have been using ARCO, and Safeway gas for the last 2+ years, just the 87 octane cheap stuff (I dump a can of injector cleaner in ~ every 3000 miles with oil changes). Now I am seriously wondering if the cheap gas gummed up my filter & the injectors. One of the mechanics at All Volvo suggested using the highest octane gas, and only from the main gas stations.

I need to get my original injectors back from the shop that fixed my problem and enquire at the injector shop. I'll have them re-tested and possibly cleaned again if needed. At least now I have spares!

Thanks for all the help you guys have given me along the way. I would be tearing my hair out (what little I have left) without the brickboard.

Mike
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1988 245, 237K mi, 5 speed