So I bought this truck a couple weeks ago and have noticed a few problems. The first one is when Im at a drive through and tap the gas a few times it feels like it wants to cut out but then will regain power. This only happens sometimes.

Second is when I am at WOT my truck will not shift into 4th gear. It sounds like it wants to at about 50mph and I can see the tachometer drop a bit but then will just keep going higher. As soon as I let off the gas it shifts into 4th gears smooth. But one time it did it rather roughly. This is a problem at all times weather hot or cold.

Another thing I noticed is at night when I downshift the lights will dim. As well as when I hit a large bump. Even braking will dim them. It's even worse when the high beams are on. (Brand new battery, alternator is good) not the biggest problem but it drives me crazy.

 

maybe run a vacumcing test on the hose pipes and see if one of the vacuum line is broke or cracked,
the other thing sound like a bad ground line/wire problem,

 

1. I'd go with dirty injectors myself.

2. Not sure why your tranny wont downshift, but perhaps the a shift seleniod isntworking properly.

3. I wouldnt worry about the lights dimming as you mentioned. I have owned two Chevys that did that.Not really
a big deal to me.You just get used to it, after a while.