Hi, im new here so not sure if this is the proper place to post, any help/experience is appreciated.


I need a little direction on where to look next, I've read some great posts but none quite the same as my problem.


I bought my truck 7 months ago, (2000 4.2 v6 2wd 5spd 111,000 miles) in great shape with a dirty but otherwise spot-free motor. I gave it a good cleaning and its come to life beautifully. I fixed the usual things; replaced ugly vacuum hoses, the PVC (and the hose to the back of the intake that always has a hole & gave the dreaded p0171/0174!) tuned it up, new fluids & stock filters, cleaned the MAS, changed the plugs & wires... ran like a top for 4,000 miles, hwy & city, with no codes.

2 months ago it began what seems like a misfire when under load but with no codes. local mechanic kept it for two days, ran every test and said he replaced TPS for weak signal but said he was stumped. SES light was on in a week. my codes are cyl. 2 misfire & lean bank 1.


I read around a little and decided to change out the Bosch plugs & wires to Motocraft, but nothing. Same two codes.


The problem is most noticeable when trying to pass, its a horrible sputtering, no-pick up mess... right when you don't want one. I've heard this complaint from others on here but it always seemed to be from owners of 2001+ 4.2 owners with the plastic plenum & bad isolator bolt issue. I have the aluminum intake & no bolts to replace.


I've been a knuckle buster for 25 years but I don't own a compression tester, obd computer or tester for injector voltage... any suggestions how to further diagnose?


2-3 miles to the local parts store I can drive, and they have my ign. coil, plenum & intake gaskets, injectors... all in stock. but I don't want to just throw parts in it. I've got 3 days off, I need my truck.


Anybody got a quality suggestion or advice to share?! Truck doesn't feel safe to drive for work any more and I fear doing more damage.
Thanks for reading.

 

I'd replace the coil pack first. I'm on the 3rd one on mine.

 

Thanks for the response. I thought if the coil pack went it would be all FUBAR? and not just one cylinder?
how did you figure out your issue?

 

The first time, it was in fact just one cylinder (#3) - it took a dealer tech to find it on a test drive with the diagnostic computer connected - this was after changing both the plugs and wires. There were no codes but he was looking at the live misfire data. Before you go buy a coil pack, remove yours and clean it up, look for carbon tracks and cracks, both top and bottom. Keep track of the wires, they are easy to get crossed.

The fact that you washed the engine kinda adds to this - those coil packs do not like to get wet.

 

...at this very moment, you, are my hero! One shot, one kill. Thank you. I too was told it had been tested and was not the problem.
I gave it another once over, no cracks or carbon tracks apparent but local parts store had one with a lifetime warranty for $80 so I grabbed it. What an amazing difference. I just took it for a 20-30 mile run, hwy & city, and she's back! Its been 2 months ugly.
I just disconnected the battery for the night and I'll hook it up and take a run in the morning to see if the CEL is off.
ill post back, but thank you for the input, you're why I joined this forum.