95 f150 4.9l m5r2, very hard starts usually requires carb cleaner to get it started. Once started idles perfect, as soon as I touch the throttle begins to choke out and miss. New plugs, wires, fuel injectors, distributor, fuel pump, coil, computer, egr valve and sensor, new iac valve new tps new map sensor checked all vacuum lines and new fuel filter. I know I'm not the only one who has had or has this problem. Been like this for almost a year. Timing is at 10° with pip removed.

 

Just to verify - you did put the SPOUT connector back in after checking the timing?

Do the computer codes post any faults?

Do you have a good blue spark? If it's more towards yellowish - may have problems as the manifold pressure rises with the opening throttle.

Have you checked fuel pressure while idling - should be around 30-35 psi. Also, a bit unusual, but the fuel pressure regulator at the end of the fuel rail has been known to fail.

With your EGR work - did you have a look at the control solenoid? It's at the other end of the vacuum line connecting to the EGR. Mine was throwing position faults, found there's a foam filter that I guess bleeds off the vacuum to close the EGR valve - filter was plugged up solid, and replacing the solenoid cleared the fault.

Mine was difficult to start if it sat for awhile, more than a couple of hours. Got around this by rolling the key On/Off two or three times before rolling on over to Start. Guessing a check valve wasn't holding, allowing the fuel to drop back to tank.

While the 4.9L is a timing gear-to-gear setup without a chain, would there be any way or reason in past history that the gears would've jumped time? Yeah, this is really reaching, but it seems you've already covered most of the Easy Button stuff.

Good luck, and keep us posted.

 

Yes spout back in, actually replaced egr, sensor, and solenoid today, same issues. When I replaced tps and map sensor and egr components all cel have since went away and none have popped up after. I just replaced fuel pressure regulator and no change. Timing is spot on. I do have issue with back tank filling in to the front tank but Ford refuses to give install or sell me the check valves because my vin isn't under the recall. Although that is not the issue. If I hold the throttle wide open rpms drop to 1000 and hold there and it sounds as if only half the cylinders are actually firing and about every 12 seconds it backfires out the throttle body, could it be out 180° on timing but consistently hold 10° btdc? I did replace distributor shortly before issues began but have been driving almost a year like that. I pulled old distributor and installed new one exactly the same.

 

Here's a possibility, the plug wires are in correct order at the distributer but are moved one forward or backward. 4.9 will idle fine like this but won't run for crap. Or distributer is a tooth off. Sounds firing related, worth checking.

 

All plug wires are in right spot and correct order. Distributor will not idle at 10° if moved one tooth in either direction. The only thing I can think of is 180° out but does anyone know if it will idle perfectly like that?

 

Well here's one more possibility. Put two fuel pumps in a truck with 4.9, not knowing at the time we had kinked the line on the rear tank. Ran fine for six months but before it died it would barely run on that tank. Idled fine but no flow to go down the road.

 

Did not disturb lines when changed pump, removed bed.

 

Pull #1 plug stuff a wet paper towel in spark plug hole turn over by hand until it blows out then line up TDC on pulley and see where your rotor is at .This is a good starting point and let you know if 180' out or not on TDC to start with. They will start 180 out.

 

Will it run and idle smoothly at 180° out?

 

Cough and spit 180 out but sure won't run.