Ok so I brought this truck about a year ago for a good price, I knew I would have some problems out of. It wouldn't go past 30 unless you put it in 2nd drive, but that would run the rpms up & felt like it was putting pressure on the engine. The guy told me the torque converter was bad, but by the time I had time to get it changed the engines rocker arms when bad. I found a deal on a engine & transmission so I went ahead & got them bothed switched out cuz for one the previous owner had the wrong transmission in. Afterwards it drove fine for about a week then went back doing the same old thing, not going past 30 unless it was in 2nd drive. I cut the converters off, changed the oxygen sensors (all but one), deleted the egr, changed the tps and the connector to it, & I cleaned the throttle body. The IAC is covered in carbon, I tried to wipe some of it all, I want to use sensor cleaner but I don't think that's the problem. There is no check engine light but I did check it & the only things that came up was the EGR needing to be cleaned or changed & the oxygen sensor I haven't changed yet. I don't know what the problem could be anymore, it's not as bad as it use to be. The rpms still run high but it doesn't feel like it's putting a lot of pressure on the engine anymore.