ncs2929

Just joined and have searched this site but fond no answers to my problem.. So here goes. I have a 1999 F-150 4X4 with 5.4l. Started rough idle and had to restart several time to get to idle, had codes checked and found bad ignition module on number 4 I replaced that it seems to idle better BUT, while driving it just dies. Put in park and it will restart. Ser. Eng light was on for bad mod. but after replaced it went out. No light now. After replacement and driving about 2 blocks it died. Now it does it more frequently. Other than this problem have never had any problems with truck.
Thanks in advance for your help

Umongus

Camshaft position sensor...maybe? My 200 7.3L Powerstroke would do the same thing. The dealer wanted $400.00 to change it. I bought one off eBay for $80.00 and did it myself in 10 minutes.

NGM

More likely the crankshaft position sensor. Since most ppl don't own a lab scope its hard to check. But if you are looking to throw parts at it, the crankshaft position sensor is where I would start.

BroganF150

sounds like the same problem that i had it was IAC (idle air control vavle) and its on the back of your throttle body. two bolts hold it on mine had trouble starting and when it did it would idle real low and the rpms would go up and down it was a 14 dollar part sometimes you can take it off and clean it and it will work i tried that but ended up replacing mine there is also an electrical connector to it good luck