87 GL10 Wagon
53K original miles
I have a nasty vibration between 2500-3500 rpm when accelerating up a hill. It happens in any gear and will go away instantly if I take my foot off the gas just a little bit (still accelerating but not as hard). But if I put it back down it comes back instantly. It feels like the car has a rev limiter on it and its dropping a cylinder. Most of the time I just take my foot off the gas or smash it to the floor to get the trans to down shift to get past the vibration. But I was on a trip recently where I was climbing a very steep hill and had to keep the pedal on the floor. It vibrated alot from 2900-3200 RPM, but kept accelerating (not as well as normal) until I got the RPMs above 3300, then it accelerated well and the vibration was gone.
I swapped tires and rims around but nothing changed. I changed the air and fuel filters, no change. I changed both front axles and wheel bearings due to ripped boots and I was hoping this issue was related to the axles but there is still no change in the vibration. Also I changed the timing belts about 6K miles ago. I feel like it has something to do with the fuel injection or the trans/torque converter.
I feel like I can live with it but I dont want it to be a sign of some catastrophic failure of sorts down the road.