Engine problem

[BLACKTIE]

Truck is a 98 Silverado with 5.7 vortec. Around town truck runs good- idles good. Out on highway it runs good while just cruising. If you let off and coast then pick up the throttle again the engine misses and jerks for a few seconds and then smooths out. Notice the same symptom when going up a hill and the engine is under load. If you really kick it down into passing gear it makes a loud stuttering "popping" noise. Almost sounds like someone rapping on the valve cover with a screw driver. Check engine light has not come on. Any help or ideas would be appreciated.

[Draenor]

I would replace fuel filter and see if it improves.

[BLACKTIE]

Just had a tune-up a few weeks ago- new plugs, dist cap/rotor, air filter, fuel filter. Did not replace plug wires- could be the culprit?

[95Sierra2500]

The plug wires could very well be the culprit. Did you put more dielectric grease in the spark plug boots (both ends) when you replaced the cap and plugs? If not you could be carbon tracking down the outside of the plugs and causing this problem (I had the same problem on my Grand Prix, turned out that I had 2 problems, carbon tracking and a bad plug wire). I can't stress enough the need to use dielectric grease when installing new plugs/wires.