1993 F150 Transmission Problem
I am having a problem (well problems) with my truck. It is a 1993 F150 5.0L automatic. Today on the drive into work, I was going down the highway at about 65mph. I went to pass someone and stepped on the gas. The RPMs went very high, and there was no acceleration, in fact, I began to decelerate. It seems as though it isn't shifting. If I get down to about 20 mph and then step on the gas it accelerates, but doesn't shift. As soon as I stop accelerating, it again only revs until I get down to about 20mph, where again I can accelerate. This is a big problem, and I am hoping it isn't the tranny itself. There wasn't any noises, no grinding, no trouble shifting before this.
Prior to this problem, I have been battling an idling problem. The truck would idle down, then rev up, then slowly come down, then rev up, etc. It does this more frequently if there is a load on the engine, for example turning on AC or turning the wheel (power stearing pump). If I disconnected the IAC, it would kill. The idle would also drop so low that it would almost kill. I changed the IAC, the O2 sensor and took the throttle body off and cleaned that. I should have changed the TPS while I had it off, but didn't. Now it runs when I disconnect the IAC. It still revs, but never gets down almost killing anymore. Now it goes between normal idle and high. If I disconnect the IAC it seems to not jump around. Also, I noticed that on the throttle body, if I disconnect the vacuum line coming in and plug it with my finger, it also seems to run fine.
I am wondering if both of these problems could be related. Vacuum leak? Unrelated? I tried the propane method of looking for vacuum leaks. Didn't find anything, but it is hard to hear any propane induced idle change when the idle is changing all the time anyway. I had it into a shop and they couldn't figure out the idle thing either, and they said they checked for vacuum leaks (all of the troubleshooting was before the shifting problem, which started about 1 hour ago on my way into work).
Thanks in advance for any help!