I've recently been having problems going up long mountain roads for instance 2-3 miles. If I go up small hills it's fine or even hills as long as a half mile, any longer then that and my truck starts bogging down and the mountain near my parents house is the worst, by time i get to the top of that it's either go full throttle or 15mph with the engine spitting and sputtering. Could the fuel filter be doing this??? I was thinking it could be the idle air control but I changed that when I had this problem the first time and it stopped which was about a month and 1/2 ago but I used the used IAC off my other throttle body from my old motor. Could it be a dieing IAC again already??? I don't hear it sucking in air like crazy like the last one did when it was dieing. Sometimes I think it would be better to just put a bunch of these under the hood and rip the damn engine out, lol.

 

Could be anything a good tune up will help. Double check the distributer position and the fuel pressure too.

 

Its definately not the IAC. The IAC doesn't do anything when your foot is on the gas. Its job is to control the idle when your foot is off the gas.

Like Crazy said, do a full tune up... plugs, wires, cap, coil, o2 sensor. Check the fuel pressure and make sure the base timing is right. The computer is going to change the timing as altitude changes, engine load changes, etc. If the base timing is off, it may run fine most of the time but won't be able to compensate when you reach a certain point.

 

Thanks for the advice.

I want to mention that this is the IAC valve: http://www2.remartautoparts.com/Items/AC10TT-TUT02 and it CAN cause that problem as happened to me less then 2 months ago. I was going up a hill and my truck started hesitating and barely made it to the top where I could pull over. I popped the hood and heard a really loud whistling noise. I took off the air intake filter, etc. and found the noises coming from the IAC because it was stuck open. I took a paperclip and kept moving the plunger on it back and forth until it moved back into proper position and then my truck began to then again idle properly and ran properly afterwords. After that I couldn't trust that IAC, so I went back to my mechanics and got the other used one off of the intake off the blown engine I had him switch out and haven't had that noise happen since. I can though imagine that the IAC could also cause engine stuttering and improper idling and driving if it doesn't open enough so that may be my problem.

Otherwise I have new plugs and wires as of 2 months ago right after the engine swap. The distributer cap and rotor were slightly used (about 6 months old from my old engine) but were inspected and in good shape so they were put back on. None of which had any cracks, breaks or signs of being unuseable or unreliable. I will however go and buy a new cap and rotor anyways since they should be bought new when you buy new plugs and wires and check to make sure the distributor is tight still after my mechanic had fixed the timing after the engine swap. Also the air filter is a re-usable K&N and was cleaned and re-installed right after the engine swap. It could be either the fuel filter and/or pump or the IAC. I'll just have to check it out. I'm wondering if there might be a computer or wiring problem that could cause the IAC to stick open or closed or not open and close properly or all the way.....Could be that the plunger and spring on the IAC is wornout and not holding it out the right amount while going up a hill and allowing it to move back and cause too much air flowing through there which is how the first one was malfunctioning(too much air flowing through not necessarily caused by a bad spring and plunger on the first IAC that malfunctioned).