we replaced the three cause we kept getting codes for miss fire on cylinders 3,6 and 8. After doing lots of try it trouble shooting. Now she just doesn't like starting at all in the mornings. act like not getting gas and doesn't want to idle enough to stay running. also bought new injectors.

 

How many miles on the truck? Plenum been checked?

Might wanna run a compression test.

 

She has about 165000 miles on her bought her in December she ran fine in cold weather was when it started getting warmer had issues. took her to a shop they messed her up more than she was. got her running good again then started throwing codes. don't know if husband check the item you suggested but we have tried everything under the sun and it irritates me. thinking of just replacing fuel pump. can't think of anything else we cleaned throttle body when first brought her home she was dirty. she just doesn't want to start in the mornings. But about an hour later will start up for my husband

 

Have a look at the plenum. (stickied thread with more info that you would ever want at top of this forum) Chances are good it's blown.

Might wanna have a look at the temp sensor as well. Make sure it is plugged in good.

What codes were/are you getting?