'89 Isuzu Trooper (2.6L 4cyl. manual) with 104,000 miles
Had to replace the thermostat a couple weeks back, and it's been running
well - until recently. It runs strong while cold, but sometime after it
warms up the power seems to fluctuate, while idle the rpm's will bounce
between 5 and 15, and when running I feel the same "bounce" in the
power. I tried a bottle of gumout in the gas tank thinking that the
problem is with the injectors, no luck.
Oil pressure appears fine, oil level is good.