1994 Volvo 940 Turbo. Automatic transmission. 132,000 miles. Now and then, upon start up, engine can’t rev up much beyond 2,000 RPM. Car can back out of garage, but in drive, can’t go forward with usual speed. Step on gas and at about 2,000 RPM, cars slows and struggles – but doesn’t stall out. Ease off on the gas and it seems to engage transmission better at a lower RPM, but still no usual speed. Ease down and up on gas and car picks up some speed but again, engine can’t go much over 2,000 RPM. Go a few hundred yards like this, get annoyed and turn off the engine and let it rest. Start up again and sometimes it runs with no problems. Other times, have to stop/rest/start a few times. It usually recovers.

The problem has always been upon start up, not when I’m driving at regular speeds and engine/transmission are engaged and working fine.

However, a few days ago, on a thruway, the problem surfaced while driving at 60 mph. Car lost ability to accelerate – it slowed down and the engine couldn’t run beyond 2,000 RMP. Pulled onto the shoulder. Tried the stop rest start routine but no luck. It never recovered. The only thing it could do was limp along on the shoulder to the first exit I could find.

Got it towed to my mechanic a day later, but upon start up, runs fine.

Problem started in cold weather. Getting more frequent as weather warms up. Much of the time, it starts and runs fine. But other times and with no warning or indication, the problem – call it hesitation, sluggishness, limping out – appears. Engine light never goes on. How does a mechanic diagnose this problem if he can’t experience it first hand? Help!!!!!