Hesitation on acceleration - fuel injectors?

[TheJMan]

Last weekend I replaced the gaskets on my Torque Monster Headers (each gasket came out in 6 pieces) and after getting everything back together I fought for nearly a day with a misfire. All the wires were connected correctly, and I replaced the spark plugs on cylinders 3, 4, and 8 with E3 plugs that had about 10,000 miles on them. The truck would hardly idle after putting it all back together, and I took the E3s out of cylinders 3 and 4. Both had rust colored deposits, and I switched them with Autolite Double Platinum plugs.

Now it idles fine and drives fine, but when I push the accelerator past about 30% from idle, it will buck, pop, and shudder for just a moment and then clear itself out. If I am gentle on the accelerator then it drives perfect.

Last week I also ran the truck extremely low on fuel. The "check gauge" light was illuminated for quite some time, and the truck took almost 20 gallons of fuel. The fuel filter was replaced at 58k miles, coil packs and wires at 75k miles, and wires have been replaced at 67k miles with the headers. Currently the truck has 95k miles and I am wondering if running so low on fuel may have caused issues with the fuel injectors.

 

[TheJMan]

Update:

I got trouble code P0304 yesterday. After pulling the code, I replaced the wire on cylinder 4, which did not cure the problem. I replaced the spark plug with a different Autolite double platinum plug, which again did not help. A last ditch effort was to replace the entire coil pack. Again the condition did not improve.

Any ideas? I'm trading this thing in on Monday and I don't want to get less money for it because it is misfiring.

 

[chapsdeva]

You may have a cracked plug. I had a similar thing happen on a 91 Civic. It would only misfire under load, but was fine under gentle acceleration and at idle. I replaced all four plugs, wires, etc. and still had the problem. Finally took it to the dealer and it turned out that one of the new plugs I put in was cracked as well..what luck!! May want to try new plugs and see if that helps.

Edit...didn't see you had replaced #4 with a second plug....sorry. The chances of both being bad are probably pretty slim.

 

[TheJMan]

I switched some of the wires around and in doing so I noticed that I replaced the #4 plug with a different E3, not an Autolite Double Platinum. After yanking out the E3 and putting in an Autolite Double Platinum, it runs great now.

 

[96eb96]

I switched some of the wires around and in doing so I noticed that I replaced the #4 plug with a different E3, not an Autolite Double Platinum. After yanking out the E3 and putting in an Autolite Double Platinum, it runs great now.

Moral of the story: Autolite or Motorcraft plugs ONLY in Ford Engines. Almost wanted post "Are you sure the E3 was out?" yesterday . Nothing else. Save the others for your lawnmower

 

[muhl5443]

sounds to mee like you have more than one bad plug or wire. if they are all fine then you have an injector problem most likely.