Hey guys. This my first and hopefully last post to this site. In the past I have always been able to find and fix any problems with my expy's, by just reading through the posts/reply's. Until rescenly. I have (2) 97 expy's, both xlt. Both with 112k.Both 5.4. Here's the problems.driving home one day the engine light came on, then started flashing. I had a old battery in it, so i replaced it. Engine light never came back on. Same day, when i put into DRIVE to leave home, the engine seemed to be running a bit rough. As I drove off it began to sputter, never dying, just like putt , putt ,putt.I Put it back into PARK and it's fine. Here is what i have replaced so far.

1. iac valve
2. pcv valve
3. egr valve

When i scanned it after the engine light came on it gave me a PO113 code. Which is an Intake Air Temp. Circuit High Input. Not to sure what that means. But I checked my Air Intake Sensor And Mass Flow Air Sensor and both are fine. It's weird because after i replaced my EGR valve I dont get the PO113 code. I know this long, but better to be long and detailed I guess. Any suggestions would help greatly and save everyone from having to read my long posts. Thanks guys for all past and future help.

 

Check the rubber elbow where the PCV line connects to the intake manifold. It is on the top, rear, center on the engine. It's difficult to see but if it has rotted out you will feel it. It is easy to check and cheap to repair with no tools required. This is a very common cause for a rough runner.

 

TPS (Throttle Positioning Sensor) could be clogged or dirty. Recommend cleaning Throttle Body using a cleaner that is designed to clean Throttle Body Housing with protective coating. I had this issue on both of my 97 5.4L Expeditions and the issue cleared up immediately.