I know you cleaned it, but the IAC may need replacement.

 

probably wouldn’t hurt to do. Gotta get around to it this weekend

 

So I had the truck running for about a week after my last problems. I went and fired her up this morning and she ran great. I went and tried to start her about 2 hours later and again, same problem. She cranks but I cant get her to turn over. This has been happening very randomly and has been on and off since I got the truck. Any help or advice is appreciate. No check engine light on. Truck is a 1999 F-150 XL 4.6L 2wd Automatic

 

What is the state of the odometer and the THEFT light when it fails to fire/start?

 

The Odometer works. Every light turns on once put to run. Once your crank all the lights turn off. It sounds like the truck wants to turn over but just won’t turn over. The theft light blinks when the truck is off though no key in ignition

 

bumping this to the top

 

There needs to be adequate fuel pressure. A pressure test is needed to eliminate the variable. Also be sure to check pressure on the regulator when the vacuum hose is removed.

 

I plan on renting the gauge to test the fuel pressure very soon. How would i check pressure on the regulator with the vacuum hose removed?

 

Hook up the gauge and turn the key on and let it prime. Should be at least 28 psi. Pull the vacuum line off the regulator, if any fuel drips out of the vacuum hose when you pull it, the regulator is bad. Reconnect the vacuum hose and start it, again minimum 28 psi. Pull the vacuum hose again, pressure should rise at least 5 psi.

 

Check the vacuum line to the regulator for gasoline first. Doesn't require the engine to be running,

The pressure reading drop when the hose is disconnected requires the engine to be running. Make sure you have minimum pressure before attempting to start. Priming cycle lasts 2-3 seconds.

 

​​​​​​​Don't you mean pressure rise?

 

​​​​​​​Rise or drop??

 

From what I can read, rise. It thinks the throttle has been opened.

 

I forget. Just look for the 5 or so psi delta as vacuum is removed or connected to the regulator with the engine running.

 

bumping this