From reading, researching and browsing this site, I have determined my problem is misfiring. When in overdrive and gradually increase acceleration, not enough to downshift, the truck will jerk a few times then smooth out. Feels like hard shifting but the transmission doesnt shift. Not problematic enough to turn on the CEL or give any codes. When I turn off the overdrive it doesn't do this. I plan on replacing my spark plugs with Motorcraft OEM because I have 50K miles on the Autozone Autocraft plugs. Thinking about changing the spark plug boots but would like to determine if I have a bad coil before changing all the boots. Anyone have any suggestions for an affordable scanner that I can purchase to do some live diagnostics so I can hopefully determine which cylinder/s are misfiring?

2004 F-150 SCrew Lariat
5.4L w/ 145,000 miles
Gryphon Tuner

 

If you have a smart phone, you can use one of cheap bluetooth OBD II readers

I have the BAFX one from Amazon that I use on my Saturn (my SCT XCal 2 works as a scanner on the truck),


I use it with the Torque App for Android and it works every bit as well, if not better than the scan tools Autozone uses. Lets you google the codes right from the app... Pretty nice setup...

 

I have a bluetooth scanner as well. I picked mine up off of newegg awhile back. I have this one actually. I also use Torque Pro app with my phone. A bluetooth capable tablet would work as well.

http://www.newegg.com/Product/Produc...9SIA1EF0F87538

 

If I were buying a scanner, I'd make sure it can read the ABS codes, too.

 

Im gonna throw in a third vote for the Torque app and a bluetooth adaptor! It helped me diagnose my misfires (COPs), and plus people seem pretty impressed if you can whip it out and scan their cars for issues right on the spot.

 

I've got this issue as well, I'd sort of put it in the back of my mind since the door lock issue has come up.
I'd be interested in which one to get as well, I've thought about the iPhone one.

 

First off I'll back up a step and say that on a misfire, if your CEL is not on the scanner is not going to tell you anything. You have to have a persistent miss for the crank to turn out of rhythm enough to trigger the fault. Only then will you get your code P0301 through P0308 noting which cylinder revs are slowing down after.

If it were me, I would have someone operate the gas and unplug each CoP until I found the one that didn't make it run worse. I would try that before the plug change, because if you have a CoP or boot issue you are dirtying up the new plugs while you are waiting to diagnose and fix it. Plus fresh plugs can make a weak CoP operate better for a short while, making the diagnosis tougher.

For scanners, I bought a bluetooth transponder for $15 (ELM 327) and paid $5 for Torque Pro. That was 2 years ago and it gets heavy use without any issues. At that price, its hard not to take a chance on it.

 

Engine misfire problem fixed. Replaced all 8 plugs and coils. The electrodes on the Autolite plugs I put in 56K miles ago were all filed to a gap of about
.070. Engine runs great now.