Check Engine Light on 2001 Silverado

I have a 2001 Silverado with 95,000 miles. About 2 months ago I had the spark plugs and wires replaced, transmission flushed, and the oil changed . Last week when I accelerated rapidly, the engine was “sluggish” and the tachometer kind of jumped all of the place. The check engine light came on ans stayed on. This problem has continued over the past week.I have noticed a sound coming from the engine (but it could be the transmission) that is hard to describe, but the best I can do is it sounds like a bunch of pinging and dinging. If I keep speeds under 60 mph, and accelerate gently all is fine. Any thoughts on what my problem could be?



wow. lots of variables. first things first.

-check what kind of fluid was put into tranny. look at invoice.

-does your truck require “premium only”? pinging makes me think of that

 However, these do not  explain gentle acceleration "all is fine". To complete the tune-up, have checked/replaced the O2 sensors. 

 Most parts stores around my area will do a free code reading with a scan tool. They've helped me many times. Try that. 

This is a LONG SHOT, but my wife has a 2000 Ford Expedition. It accelerated just fine gently, but under heavy it was kind of missing/sluggish. After replacing many parts and giving up, I took it to a shop and learned something. This 5.4L Triton has a coil built in the the actual wire, lack of better terms the coil sat directly on the spark plug. From what I read, you had wires replaced. Is there any chance it has same set-up or a coil pack? The conclusion to my wife's truck, the tech gather up his lap-top plugged it in and said, "Let's go for a ride." He showed me the screen. It had 8 bars and a line in each flying all over the place. The Number 1 cylinder was dropping out. He replaced that coil and ever since then the truck runs like the dickens! It also go 21.5 mpg. 
In conclusion, see if a local parts store can read your code.

Hope we can help you, Jimmy.