We are the proud new owners of a 1992 fox body. I might post more about that later. For now, I have a drivability issue I'm trying to do some diagnosis on myself before getting it off to the mechanic next week for some TLC.
Symptom: Low power above maybe 1,500 RPM.
Taking off from a start with moderate throttle it pulls ok until about 2,000 RPM then the power just sort of levels off at what feels like 4 cylinder acceleration. While driving at 35-45, I can push the throttle right into the floor and at first nothing happens. No acceleration, no downshift. After 1-2 seconds, very slowly, it revs a small amount and eventually downshifts....but the movement forward is weak. Interestingly, if very easy on the throttle, maybe 10-20%, it seems to move forward as expected for that amount of throttle.
No misfires, no backfires. I'm no expert to listening to engines but it sounds "good" no matter the RPM range. I did hook up a vacuum gage to the tree, first by the speed control port then again by the AC port. At idle it's 18in. 2,000 RPM sends it to about 22in. 3,000 gets it to just under 25in. The needle is steady as long as I keep my foot in the same spot on the gas. I know that's not a complete diagnosis, but I think it doesn't have a major vacuum leak.
I was thinking maybe fuel filter, but if it was being starved due to the filter, pump, or injectors it would probably lean out and misfire or backfire, wouldn't it?
Anything else I should armchair diagnose in my driveway?
Symptom: Low power above maybe 1,500 RPM.
Taking off from a start with moderate throttle it pulls ok until about 2,000 RPM then the power just sort of levels off at what feels like 4 cylinder acceleration. While driving at 35-45, I can push the throttle right into the floor and at first nothing happens. No acceleration, no downshift. After 1-2 seconds, very slowly, it revs a small amount and eventually downshifts....but the movement forward is weak. Interestingly, if very easy on the throttle, maybe 10-20%, it seems to move forward as expected for that amount of throttle.
No misfires, no backfires. I'm no expert to listening to engines but it sounds "good" no matter the RPM range. I did hook up a vacuum gage to the tree, first by the speed control port then again by the AC port. At idle it's 18in. 2,000 RPM sends it to about 22in. 3,000 gets it to just under 25in. The needle is steady as long as I keep my foot in the same spot on the gas. I know that's not a complete diagnosis, but I think it doesn't have a major vacuum leak.
I was thinking maybe fuel filter, but if it was being starved due to the filter, pump, or injectors it would probably lean out and misfire or backfire, wouldn't it?
Anything else I should armchair diagnose in my driveway?
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