94 850 sluggish acceleration

jamesstar9 · Post by **jamesstar9** » 17 Apr 2011, 20:56

I have a 94 non turbo 850 wagon. I am having acceleration problems. It starts fine but when i try to accelerate the car putters and is dangerously slow till I get it enough gas to finely get up to speed then it will run fine in higher gears. This happens every time I am at a stoplight and try to go. I have tried cleaning the pcv valve and checked for vacuum leaks, broken elbows, etc. I have replaced the fuel pump, fuel filter, and spark plugs with no improvement. The only code its thrown is A2 221. Not sure what is causing the problem any help possible causes would be appreciated.

Post by **jblackburn** » 17 Apr 2011, 22:49

"Long term fuel mixture trim too rich"

What happens if you unplug your mass airflow sensor (engine off) and try to start it up and go for a drive? I think you may have a bad MAF sensor - they tend to fail pretty often.

jamesstar9 · Post by **jamesstar9** » 20 Apr 2011, 12:53

I tried unplugging the MAF sensor and starting it up. I can hardly get the car to move without it dying. What about the EGR valve. I read you can clean it. Do you think this would make any difference in driveability?

Post by **jblackburn** » 20 Apr 2011, 15:49

Start looking for an air leak - it should be able to run off a "best guess" estimate without the MAF plugged in. In your case, you're looking for a big leak - turbo intercooler hoses can develop a hole, as can the actual intercooler itself if you smash into a curb or something. Both intake manifold and throttle body gaskets can go bad. If the car doesn't know exactly how much air is being metered into the engine, it will throw off the A/F ratio and cause it to run rich like it's complaining about.

There is another possibility in that the purge valve (it's a cylindrical valve on the radiator near the battery - follow the 3 hoses from it into the intake manifold) is stuck open. Pull off the hose from that to the intake manifold and try it out quickly; does drivability improve?

markinbc · Post by **markinbc** » 25 Apr 2011, 12:22

I had a similar problem on my 740TI, turned out to be a dirty knock sensor which was retarding the timing in first gear. I cleaned it and ran 100% ever since. It was cheap and easy to replace so I did that anyway.

On the 850 however you have two at $80/each and they are behind the exhaust manifold. If you get that far might as well look into cleaning the PCV system if it has been awhile.