93 940 wagon non turbo w/regina.

Been fiddling with this off/on for a while (always have spare cars kicking around. But this is my nicest Volvo and has working AC so time to stop playing amateur night here and ask for help.

I have limited mechanical ability but above avg (I also own several MGs so I am not bad at basic process of elimination diagnosis). Some tools but no fancy Fuel Pressure gauges etc.

The car has been fine but it was leaking lots of coolant over a period from a bad donut gasket at the water pump. The car seemed to have a couple of over heating issues during the spring causing boil over from a 'not' tightened cap (remember, bad gasket). This did cause some coolant spray in the passenger side of the engine bay. Last time it ran fine my wife was taking it to work. She got maybe 3-4 miles from home, car lost power and died on her. I brought her another one of the wagons so she could get to work. It had appeared to overheat but symptoms would not go away after cooling (would run for a short bit down the road and then power would drop to maybe 20% and I would shut down. Finally towed it home. I figured it was high time I tackle a water pump replacement and did just that which went for me, better than avg.and although not supper pro, it holds coolant better than before by leaps and bounds. But the car has this persistant problem of start up and it runs fine at idle (600 rpm) for a minute or so, or drive down road 200-300 yards or so and then the car starts running very bad and can only be limped home by using the power I would get by depressing the throttle and then letting it go whereupon I would get a small surge of power. Had it towed to my Brit car mechanic who loves the old bricks and drives them himself. He thought it sounded like fuel pump perhaps (at 240k, I was not going to hold it against Volvo). We (he) changed the pump and relay and I picked it up from his place AFTER he had driven it for 12 miles and then ran it for 27 minutes in the drive way fine. I got 1/2 mile up road and same running problems came back. limped back there, he was starting to get stumped. With the car idling like crap, he unplugged what he thought was the air mass flow meter and when he did, the car idled fine and I limped it home with no problem (limped is a bad term, it drove fine the 12 miles to my home). I shut the car off restarted it and the problem came back !?! and I have had it since

I found out the next morning it does not have a a air mass meter (regina) (I am learning here. In it's place is an air temp sensor, I replaced that with one from another of my wagons and after cleaning it with MAF spray cleaner (seems just like electrical contact cleaner) and installing that, the car still made the symptoms.

Check codes (new thing for me). I got a 221 (or whatever the code for O2 sensor is) and that was all. Ordered an O2 sensor and went to install it and found the hole for the sensor was welded up (I would guess by prev owner). So, not the problem obviously and now I have a brand new NGK sensor from EEuroparts here that I do not need. (btw, we also have changed the fuel injector relay and coolant temp sensor on the block either during this or in the last year. Started reading here in the great FAQ section. Hard to find Regina info but I did go and check the radio noise suppresion relay with a good one from my other Regina car (91 740) That did not help.

SOOOoooo.

Here are the current details that I can relate. car starts great, idles great for 1-2 minutes, then idle starts bouncing between 600-900 rpm gradually getting worse, missing ans then stalling. HOWEVER, if when it starts getting rough I raise the rpms to above 2000 and bounce it between 200 and 2500 or 3000, it will run like a champ at that rpm range but not at a steady throttle. Only if I keep bouncing the rpms.

HELP Please!