97 5.4 Auto, Hypertech programmer(installed a couple of weeks before problem occured), Airforce One intake, 60,000 mi on engine.
Had the truck since 40,000mi. Got out of the military. Sat for 3 weeks awhile back due to waiting on title paperwork so I could tag it, started twice during this time. Once tagged I fueled it and drove. Then noticed a chugging or "miss" during acceleration and on hills or under load. Non consistent. Idled fine, reved fine. Became worse especially on hills. Check engine started flashing then stabilized and stayed on. 1st. thought fuel problem. 2nd. thought spark plugs. Ran fuel treatment (thought maybe water in the fuel)didn't seem to help. Went home Programmed the factory settings back (which obviously got rid of the check engine light). Ran diagnosis and no code was stored due to getting ride of the hypertech(cleared everything). Installed a new fuel filter. Did alittle better. Cleared up mostly but not immediately. couple of weeks passed. Then reoccured. Finally got the check engine light to come back on. Ran a diagnosis. Said # 2 cylinder miss fire. Did nothing, cleared up mostly but still just didn't seem right. Week or two passed. Put new plugs in it. Reprogrammed the hypertech. Ran like a top for a couple of days now I have the chugging and missing again but at lower rpm and not under a load. Not gotten bad enough for the Check engine light to come on again but it's noticable.
(Keep in mind all this took place over a period of maybe 3 weeks to a month. Letting it set for a day or two in between each thing that happened or I did, due to not having time to work on it. The problem stopped or decreased and then reoccured a few times during this).
Could this be due to a problem with the hypertech or airforce one possibly? My coil packs looked ok. Fuel pump maybe? Fuel regulator's? Fuel injector's? Running out of cheaper quick fix possibilities. Any advice would be greatly appreciated.

 

Try looking at the plug wire or replacing the coil for that cylinder.

Scott

 

Thanks Spieldawg. Thats looking like my next step. I had a diagnosis ran on it yesterday and it said #3 cylinder missfire this time. One possibility is that when I replaced the spark plugs #2 and #3 coilpacks got mixed up when putting them back on. So I'm gonna put #3 coil pack on #1 cylinder and see if I can get a miss fire there.....that would solve it all and only cost me $54.99 for a new coil pack. By the way are you at anderson AFB?

Josh

 

Yep, you got it. Only 86 more days on the rock... then on to Travis AFB CA

Scott

 

Got out of the AF in jan. Finished up at Osan. Got several buddies at Anderson. Do you know any Ammo Troops?

 

40 minutes into frisco...check out lake berryessa...used to be able to jump off the cliffs near the "Glory hole" at the dam...any way...check Jefflaws posts about egr tubes and the vac tube running up to the throttle body area...sounds like you have a vacume leak.... you can ohm out your coils ..search my posts,i described it a couple of months ago...good luck

 

My next door neighbor is an ammo troop...Carden. I was at travis for 5 years before I got here. Its nica area

Scott