GMC sierra engine is cutting out at times?
The engine is a 5.3 liter. At times the engine idles rough. Also, misses or cuts out between 40 and 50 miles an hour at low rpms. I tried fuel injector cleaner, took to dealer. They put a new fuel pump on it. Nothing changed. I also tried an engine recorder from the dealer and everything came back as normal. Spark plugs are also new. What could be the problem? A: It could be the plug wires like the other guy said but if you brought it to the Dealer for this problem and they shot gun (throwing parts) a fuel pump at it and it did not fix it I would be right back there asking questions on why this did not take care of the problem. the ECM should have a code in it for a misfire on a cylinder if it starts missing on two back to back trips. If I let a truck go that I had worked on that still ran like poo after working on it the boss would have me in his office asking why. Good Luck. Ps did they/you put a new fuel filter on it also?
