Replaced the plugs.....didn't help. Replaced plug wires....didn't help.
Replaced the coil pack.....cleared it up for maybe 100 miles and now the misfire is back. Not as bad as before but it is there. Getting irritated.

I like the ride of the truck but I can't be replacing parts like this left and right.

 

What size engine ?

 

It is a 2004 heritage stick shift with the 4.2 V6.

 

When I give it throttle the engine light stays on. When I baby it, the engine light blinks. I have to drive it in a lower gear than I normally would.

From my understanding, the blinking light shuts down a injector to try and save the cat converter.....not sure if this is true or not.

 

What codes are showing up?

 

The blinking light means possible damage to the convertors if you continue driving it.

 

Yes just like before we need the codes. And how many miles are on the truck? If I'm not mistaken your truck has the C.O.P. design, correct? How many coils have been replaced? Misfires just so you know can be caused by many different factors. It could be fuel related i.e. faulty injectors, vacuum leaks to air/ fuel mixture. Like a faulty mass air sensor or even a faulty O2 sensor. Or dare I say a bad cylinder for a number of different reasons for that circumstance as well. So we really do need the codes as a starting point. Then we can help proper diagnose the issue. And so you don't waste money by throwing parts at it.

 

The truck only has 45,000 miles on it. I had to work overtime late last night and I slept in this morning. I will drive the truck to advance on Monday and have the codes read.

 

Codesp0302 misfire on cyl #2, 0305 misfire on cyl #5, p0306 misfire on cyl 6

 

I think the problem is the soon to be x wife. Before I touched anything under the hood I had misfires. So I was careful to replace the plugs one at a time. I also replaced the aired one at a time when I switched the single unit coil pack I did it one wire at a time.

Well I got the repair manual out and it seems someone crawled under the truck and switched the wires on the 5 and 6 spark plug. This would help explain the misfire before and after I replaced all of the plugs, wires and coil.
Truck runs like new now. The check engine light is on but I have not cleared the codes yet.
Might also explain why I had no brakes about a month ago.
She wouldn't do it herself bit she has a friend and a brother that would.
BTW ....The 130,000 life insurance has a new beneficiary.

 

Either your cats are clogged, O2 sensor is messed up or a bad injector OBD-II Trouble Code: P0302 Cylinder 2 Two Misfire Detected

 

I cleared the codes and one popped back up. P0430, Catalyst efficiency below threshold bank 2.

misfire ok
fuel sys ok
comp component ok
oxy sens mon ok
oxy sens htr ok

4.2 V6 2004 with only 46,000 miles.

Looks like I will be replacing a cat or two soonish. The inspection sticker is up in September.

Note: truck runs fine after replacing the plugs, plug wires and coil. It was the coil that was causing the misfire. I will add that the platinum plugs on the drivers side seemed a little to worn for only 46,000 miles. I replaced with plain copper auto lite plugs.

 

How about a proper diagnosis first. Check to see if they are clogged. Check to see if the o2 sensors are functioning correctly. Don't waste money by throwing parts at it. At 45k on the clock, I'd bet you have a faulty o2 sensor before a bad cat. These tests are relatively easy to perform as well. A simple infra red thermometer will tell you if the cat is clogged. And a multi meter measure the volts and resistance of the o2 sensors will tell you if they are bad. Just throwing parts at it will make you hate the truck. I also don't understand why you think your wife has something to do with it. You can't always go by what the computer is saying in relation to sensors being accurate if they are bad. A manual check is the best way.