I am new to the forum. I have a 1988 Pathfinder SE-V6 with 316K miles on it and it has an automatic transmission (the trans was replaced 500 miles ago). Recently when I was driving, I experienced a problem with acceleration. I was on the highway going up a hill, and to maintain speed I gave it some gas, when it down shifted to get more power it hit 4100 rpm and started to become sporadic ( rpm fluctuating and engine cutting in and out). This only lasted until I let off the gas pedal a little. I discovered if I didn't press the gas pedal too aggressively it will maintain speed, shift and accelerate fine. On the way home the problem seemed to get worse. It got so bad I couldn't even get past 40MPH, any time the rpms would try to pass 2,000 rpm the engine would start to cut in and out sporadically. I eventually pulled over and turned the pathfinder off for ten minutes. This seemed temporarily fix the problem or reset the vehicle for about 15 minutes. So I kept doing this until I made it the rest of the way home. The next day I took it out for a little while maybe for an hour and it didn't have any problems until the last 10 or 15 minutes. If I put it in neutral the problem isn't present , only when it's in gear. It seems after the car has been sitting a while without running the problem is nonexistent, until it warms up. The longer it runs the worse the problem gets. I have checked the ECU for falts in Mode 3 and received a 55 which from what I read means no faults present. Please help!