Well I had a tech from Caterpillar look at it and he said the filter was plugged. He left and I replaced it...same problem. He returned and told me to disassemble the throttle body and clean it...same problem. The tech was stumped. He plugged into it and he pinned the throttle and said that he reset the perameters in the computer. He said by going wide open throttle you can reset your perameters. I didnt believe him and think he is still unsure how he fixed it but the problem has not come back. I also mentioned to him that the temp guage was not working and I figured it was perhaps the computer thinking it was cold and going into a 'warm up' mode and choking back the throttle body? The forklift has been operating for a few weeks now though. Sorry bud I cant really help. I think you need a tech to plug into it with cat software.