sandman

I have a 2005 F150 purchased new with the 4.2L. It only has 8K miles on it and has had a starting problem since new. Every once in a while (maybe not for a month, maybe not for 6 months) it will just crank with no firing, this may go on for 2 or 10 tries, and when it does finally fire, it bangs (like it's firing on the up stroke) and runs rough for a few minutes until it settles down. Doesn't seem to matter if it's hot or cold outside, if the engine is hot or cold or anything else. I've had it into the dealer, but of course there are no codes, and it always fires for them.
Today it was the worst. It would crack and then kick back hard against the starter. This went on for many tries until it finally started, running terrible, and the tach and speedo were both at 0 and wobbling. We shut it off, and then it wouldn't start again, just kicking back. When it finally started this time, same thing with the tach and speedo. All the other gauges seemed fine. We started driving, and about 30 seconds later the tach and speedo came on. This has got to be a clue as to what is happening!
The truck always runs good when it's running, and the engine has never even stumbled. The ignition tumbler was changed when it was new as it was binding, but that's all that has been done.
Sorry for being so long winded, but this is getting frustrating as you never know when it's going to happen. I suspected the crank or cam position sensors or the ecm since it seems to misfire when it kicks back, but the engine always runs perfect when it starts. I still think the tach acting up has got to be a clue.

Any help is appreciated.
Darryl

wde3477

Sounds like you're looking at the same stuff that came to my mind. It's as if the ignition timing gets way off for whatever reason.

Intermittent problems are the worst kind - there long enough to be a nuisance, but not long enough to figure out what it is.