Hey Folks, my 2002 Screw (199,695 miles) is throwing codes P1290, P1285, P1299 and running rough eventually stalling. Now I know what each code is but let me add some more details. I have a Gryphon Programmer so I can keep tabs on engine temp, etc. I drove my truck no more than 3 miles today and it started running rough, threw the codes and died but before quitting my gauges went nuts. I had a half tank of gas and my fuel gauge went to full. My temp gauge went as high as it would go then fall but on the Gryphon the temps on the cylinder head started jumping all over the place (from 190 to 240 to 350 back to 218 and kept cycling). The truck has plenty of coolant and oil. Oh and a week or so ago I noticed that upon starting first thing in the morning I had a misfire on cylinder one. Over the years that happens occasionally and may be unrelated but it's worth throwing out there.

I think maybe the cylinder head temp sensor is shorting out and needs to be replaced but would like to get your input before I start this and that taking pot shots at it. Thanks in advance.

2002 Screw, 5.4L 199,695 miles, Auto Trans

 

We found a crack in the intake manifold just below the radiator hose with a good bit of corrosion underneath. Also believe the CHT sensor just above the leak has shorted as a result. So Monday we will replace the IM with a Dorman, change the sensor(s) and the thermostat and see what happens.

 

The CHT is below the intake.

 

You're right. I meant below and typed above anyway.

 

In case anyone is interested in the outcome we're running smooth again after new intake, CHT sensor, new plugs and cops.

 

Good deal. Thanks for reporting back.