Hey guys, got an issue with the truck. I no longer have the 2003 I have a 99 f150 4.2 and a 5 speed. Its got 200,000 miles on it. Well couple weeks ago cylinder broke the l broke the exhaust valve spring. So I decided to replace it along with the wornout timing chain. So I get all that done and it's running great. Now I have a cylinder a and 4 misfire so I decided to do a complete tune up and call an and coil pack. Well it didn't change anything. So now I'm at a loss of what to do. Any advice would be much appreciated.

 

Sorry guys im doing this all on my mobile phone so please bear with me. Number 6 is the cylinder that broke the exhaust value spring. And cylinders number 3 and 4 are the ones misfiring.

 

You changed the plugs, wires, and coil pack? What brand parts did you use? Did you use dielectric grease?

 

Yes, yes, yes. Motorcraft plugs, and quality wire and pack. Dont remember the names but I paid out the butt for them.

 

Just a shot in the dark.......but the earlier 4.2's had a different firing order than the later ones. Not sure when it changed, but worth a look see.

 

Just checked the gap on all the plugs. Spot on. Checked the firing order, spot on. Checked the wires they seem fine. Im at a loss here.

 

So, I was thinking, when i put the harmonic balancer back on the ring for the crank sensor broke in 2 so I had to get a new one. The only place in town that had one was Advanced which is not my choice store. What do you guys think of the balancer being wrong, say since it after market and not oe. The ring on the original one was aluminum and the new one was steel. Could it be possible this small difference can cause these codes. Ive looked at pics of the rings oe and after market and the space in between teeth seem slightly off to my eye.

 

Turned out to be a bit of carbon build up in the engine. So I seafoamed it and no codes or issues. Thanks for your guys help