We have owned this car for a year and few months now, all around decent car except it has this problem every once in a while. When you go to accelerate the engine cuts out backfires, has little power but when you back off the throttle it returns to normal around part throttle the problem is also more frequent under extreme ambient tempatures hot or clold (under 3000 R.P.M. ). I owned a chevy 4x4 truck with the 350 small block that had the same symptoms. that was fixed by a general tune up (filters, plugs, wires, cap rotor etc) and a weak ignition coil was replaced so I thought that it was the same problem and i have replaced the old plugs wires cap and rotor, also the coil was weak so it was replaced with a MSD blaster II coil. Also i have replaced the fuel filter and ensured the engine is getting adiquate fuel and spark and the problem still persists.

My expierence with volvos is limited. Previous to this ones i have owned were not for driving daily Ive had a few 240 wagons that were set up for the compact demolition derby. But in those cases i never ran a volvo engine always swaped a ford 2.3 4cyl from the pinto or fox body mustang those volvo wagons are built like tanks lol but i am getting off topic.

Anyways I have come to this forum because no one knows volvos like you guys. I mostly worked on domestics and diesel power like chevy 350's etc and japanese imports. It does show a check engine code occasionally sometimes constantly some times it does not throw a code. Is there a computer connector on this car so you can pull codes or does the computer have to be removed and connected to a scan tool. Ive been told it could be the t.p.s. or the o2 sensor but want to be sure before buying a part that does not fix it so. what do you guys think could be the problem. this has been driving me a little crazy, and i like the car and would prefer to keep it around and not let it end up in the same fate as those wagons previously mentioned. anyone have any idea what the problem could be

 

a 92 Turbo has LH2.4 injection, which has an onboard diagnostic dohickey on the left fender well under the hood. you can read the codes as blinking light sequences, and you don't need any code readers.
see Engine and OBD Diagnostic Codes

note in particular, the jumper in position 2 gives you fuel injection codes, and jumper in #6 gives you ignition codes. DTM#1 reads the diagnostic codes, DTM#2 tests the sensors (and is a fairly involved procedure), and DTM#3 exercises various actuators (handy for verifying that the engine electricals are doing their thing).



when *I* had a power cutout problem like you (heavy throttle, mid gear, moderately high RPM heading for the top), it turned out to be the airhose between the airbox and the turbo was not properly connected at the turbo end, and under high airflow, it was sucking in and flapping, which was causing all kinda stuff to go whack.

 

Also remove the air flow meter from the top of the airbox and check the screen on the intake side of it. The turbos have soundproofing foam on the lid of the airbox, it decays over time and blocks the mesh screen.
When I first bought my 740 turbo, it would drive around town fine and even take fairly decent amounts of throttle and load, but give it full throttle and heavy load and it would die like it ran out of fuel and backfire until load was dropped right back by reducing throttle.
Another problem can very occasionally be the rubber intake hose from airbox to turbo collapsing under load.

 

that last is exactly what I had experienced, under full throttle loads in midrange gears, heading for the top end, suddenly phlapflopflopflop and no power and hte turbo needle would be bouncing like crazy. back off the throttle, and roll it back on and power would be normal until i exceeded the same limit.