Please help! I have spent all weekend working on my truck and it still has a problem. Initially it runs great but about5-10 worth of driving it will not go over 2000 rpms. it just falls flat on its face! It acts like it is choking. I have replaced the fuel pump and filter and done a tune up on it but it still does the same thing. I have also checked all vacume hoses and no leaks there.

Please Help!

 

Is the cat convertor glowing? Take a look at the instructions for your vacuum gauge and do the test for a clogged exhaust. Have you taken 2 minutes to pull any trouble codes?

 

Please explain a little bit more.. I am so tierd of working on this truck! It only has 90k miles on it and I am about ready to get rid of it..

 

Yeah, at 90K it's not even broken in yet. I always figure my cars or trucks are nicely broken in at 100K & ready to go another 100K before I trade.
See if any parts stores will loan you a vauum gauge, then just follow the directions that come with the gauge for how to hook it up & test.
If you dont want to spend 25 bucks for an EEC-4 code scanner check out the tech info sticky at the top of the Ranger forum for how to pull EEC-4 trouble codes. Once you have the codes, post them here.

 

If you have good eyes and can count quick, you can read the codes from the flashing of the check engine light. Just need a wire jumper. Procedure is in tech section of www.batauto.com Have you ever seen a check engine light? Like many here, you jump to a conclusion and don't test the theory before buying a part. Fuel pressure test or even pump current would have told you that the pump was ok. Any more details you can give us like how it idles after that warm up period. Things that happen after about the same time after startup often have something to do with the emissions system which is inhibited durring warmup. EGR could be a possibility.