I have had my truck in differant shops and the mechanics have spent numerous hours working to try and find out why my truck runs so bad. It doesn't seem to shift properly as I can put the peddle to the floor and I can not spin no tires. It doesn't seem to have the power to clime hills as it semms to shift to late. It starts good and and runs ok but no power when punching it. Also my milage has gotten terrible. The last garage put on an exaust changed full filter and computer chip.

 

You need to check the fuel pressure. Pump might be just starting to go out. Check the spark plugs and their gap. What did the garage check so far? When was the last time it was tuned up?

 

When the exhaust was changed, did they check or replace the cat's ? Sometimes a clogged converter causes the symptoms that you described.

 

im assuming that your truck is a carb'ed truck so it could be your carb the jets might be faulty alot of times if there is water or moisture in the gas tank it can run the jets and cause the lack of power.