My wife has a 2002 Saturn Vue with the 2.2L 4cyl engine and a manual transmission. Yesterday she started it in the morning and backed out of the driveway. When she put it in first gear and tried to accelerate, the engine lost power and the car crept along around 5mph. The SES light came on as well. She took it to Autozone and they plugged it in but did not get any codes from it. I disconnected the battery today for about an hour, reconnected it(thinking it might be a computer issue?) and then test drove it and got the same result but this time without the SES light. The engine revs just fine out of gear or when in first gear and not trying to accelerate. It seems to only lose power when under load. Any ideas? I’m lost.
With no codes to provide a clue, it’s hard to tell. It could be the ECM (computer) is confused and going into limp mode, which limits the max speed allowed probably. I’m guessing there probably are codes, but for some reason they didn’t show up w/the scan tool that was used at Autozone. It’s probably worth your time to take it to an inde mechanic or a Saturn dealership (well, a dealership that services Saturns) and try the code read thing again.
If I had this problem on my own car and didn’t want to bother w/the codes I’d check the battery voltage was correct and stable and no unusual electrical noise on the +12 line from the alternator (which could confuse the ECM). Next I’d bring all the routine engine maintenance up to date, then I’d check the fuel pressure.