I have a 97 4.2L V6... I bought the truck used 2 years back with the engine and transmission rebuilt about 10,000 miles prior. The truck ran great. Probably one of the smoothest 4.2's ive ever driven (and I work at a car shop, ive seen plenty of 4.2's roll through there)

Well about 6 months after I bought the truck I was T-Boned in the truck. Found the identical truck on craigslist with a bad 4.2L in it. Bought it and proceeded to take on the longest project ever, engine swap.

While the engine was out I changed quite a few things on it just because I could crawl all over the engine easily.

List of things replaced:
- Spark Plugs
- Plug Wires
- Alternator
- Power Steering Pump
- Water Pump
- Thermostat

There were more items but not necessary for this topic.

3 months of working when I could and a dictionary full of cussing and swearing from myself and my dad (who owns the car shop I work at) it was finished.


Fast forward to last winter (a little over a year of me owning the truck, or engine, however you look at it...) the truck would run fine unless it was cold really cold out. I installed a remote starter on the truck right before winter.

I started the truck with the remote starter waited about 10 mins then went out to a NOT running truck. The remote starter is programmed to run 24 mins before shutting off (I know this I programmed it).

Frustrated I hopped in started it with the key and it chugged and sputtered and idled so rough it the truck was shaking after about 10-15 seconds of that it wound up to normal idle and was fine...

Since last winter the truck has done it probably once a month (its like a female).

Now I am seeking advice because this past Friday I stopped at my house shut off the truck went inside to grab something for a second... came back out hopped in fired it up and then it started sputtering worse then I can ever remember... even misfired about 3 times, it chugged for about 2 mins almost stalling a couple times. Finally revved up to normal idle and off I went. Hasnt done it since but this was the 3rd time in about 3 weeks.

Talked to a couple Ford service write-ups and some Ford mechanics I know they said Plugs and Wires (Unfortunately I can't remember what I put in last time). One of them said take a spray bottle and mist my coil pack and wires and see if it starts into sputtering to see if they have cracks that dew is getting into.

Anyone else got any ideas? Coil pack gone bad? Plugs and Wires? Good brands for plugs and wires? IAC Valve? PCV Valve?

Im willing to try just about anything cause it sputtering like that sure as hell cant be good.

 

That's an excellent suggestion. I had a coil pack that would cause a nasty miss when it was damp out.

Clean or replace the IAC, clean the throttle body, run some injector cleaner (Techron recommended) through the gas. Have you checked for OBD2 codes?

MOTORCRAFT.

 

Will do on the plugs and wires. It hasnt been all that damp out the past few days so I will do it anyways seeing as you said it could be the issue.

Ill look into running the cleaner through it and replacing the IAC.

 

Try cleaning the IAC first - remove it and spray it out with WD-40 and work the plunger with a screwdriver. The TB should be removed to clean it, use TB cleaner.

If you have replaced the plugs and wires, the problem is more likely the coil pack than those.

 

Ok ill take a crack at it and see what my results are...