I'm still trying to trace the root of my X's problems and today while at Auto Zone, I had them run a battery/starter/alternator test and the batt and alt passed but the starter failed by drawing 280 amps...

When I first crank up the truck in the cold mornings, it idles perfect and shifts perfect (although a little soft) but after only a few minutes to warm up, I get a "miss" at idle and the trans intermittently shifts hard from 2-3.

The Torque app says I have a bunch of misfires at idle that go away while driving - does that sound like a vacuum leak?

Anyways, I am determined to get the X back in shape and will greatly appreciate any troubleshooting tips or tricks.

 

Get a code reader... the misfire/stuttering could be coil, vacuum leak, IAC, etc...

Starter just turns the engine over to start.

I'm assuming this is a 5.4/6.8 truck?

 

No.

Sounds like you will need a new starter soon, but that's not the source of your issue.

Lots of times a bad coil will first cause issues when the engine gets hot. Are you getting a misfire code? Sadly the OBD-I compliant PCMs in these things are nearly braindead when it comes to misfire detection.

Possibly a vacuum leak, but I don't think it's likely that a leak would seal itself when the engine is cold and cause misfires when it warms up.

 

No on the starter

 

I'm thinking I have multiple issues but man, there's nothing obvious! I've gone over all the lines, wires, and hoses in this truck looking for issues but nothing... I have had the truck to different mechs at different times and nobody has found anything. I will admit that I'm NOT impressed with any mechanic I've spoken with though.

Maybe I should start throwing money at it? I'm pretty sure I don't have a plug and coil issue as they've all been replaced AND I have new spares that I have used to "check" for issues.

The injectors were all super clean and orings were in good shape. I haven't done a compression test yet but honestly, I think it would be unnecessary. Oh well, I'll keep trying.

 

Lots of times when the trans shifts into 2-3 the torque converter will lock up at nearly the same time causing a harsh shift feeling.

As for the missing and COP's, did you get new cop's, rebuilt, oem?

Hopefully it isn't a coolant issue. Has your coolant been going down at all?

 

I tried new Springs and boots first and got nothing then I bought a couple new ones to swap out and nothing then I got new motorcraft coils and plugs and still have the"miss" issue...

Coolant is fine.

It blows white smoke occasionally and I wonder if the cat may be partially blocked...

 

You need to get it to a shop who can run a cylinder contribution test. It will show live data for each cylinder and will help narrow it down. Some shops may refer to the test as a 'mode 6' test and they may have an older scan tool but either one will work for you.

 

Been there done that... its not the plugs or coils.

 

ECU or injector module?

No codes at all?

When the motor was replaced was it just a long block? Did it have a intake, all sensors, and whatnot on it?

 

As far as I know the motor is original along with everything else.

No codes which is why this is so maddening.

 

Sorry about the motor replaced comment, I was thinking of another thread of someone who had their motor replaced because of a problem.

 

No worries. Just at a loss with this truck. ..