Have a 1997 Chevy Silverado 1500 k 5.7 l V8 Vortec engine got to push button 4-wheel drive I recently have changed fuel pump fuel filter both of those have been done within the last six to eight months nine months ago I changed all the spark plugs, spark plug wires. Six months ago I gave it a new vacuum booster, I also changed the master brake cylinder gave it all new brakes all the way around.

Now I'm faced with a new problem.

At around 55 60 miles an hour for anything more than 5 or 10 minutes it does fine but after that 5 or 10 minutes it dies down bogs out the RPMs drop to in between 1 and 2 and just fluctuates up and down back and forth between 1 and 2 even though your foot is just steady in one position on the gas. You're not gaining any speed giving it gas after about four and a half five minutes doing this it then starts to slow down and starts popping AND chugging, sounds like crap. All winter long it's been hard to start I assumed it was because of the weather because it was so super cold out that's why I was hard to start. Also I'm going through full bottle of antifreeze every week in a radiator although I can't find any leaks also add stop position if you give it gas it goes very slow very slow to accelerate. Somebody point me in the right direction I've been working on this truck myself for a long time it is my daily driver I got to get it back to good working order thank you.