Jray215

Hello all. I've been sneaking around here for sometime and have seen similar issues with other trucks but noting exactly the same. Please help if you can.

Ok. the truck has been running very good for sometime and just recently it has started giving me major issues. About three weeks ago while driving home, I approached an intersection and the truck just died. I coasted to the side of the road and put it in park. I cranked it right up and ran fine for several days. On another trip around town the same thing happened. When it died I shifted to N and fired it right back up. As I approached town I came up to another intersection and the same thing happened again. Same scenario, put in N and cranked it back up.

The problem continued and I was advised to change my fuel filter. I changed the filter and the problem is now worse than before. I cant make it more than 100 feet before the truck dies.

The strange thing to me is that the truck idles fine and if the truck is in park or neutral I can reeve the engine high and there are no issues. If the truck is in gear it idles fine. when I let off the break and start to roll is when the problems start. If I give the truck gas and get to about 10mph it dies. It does not sputter, it just dies. If I let my foot off the break and let it roll at idle speed and feather the gas it will stay running as long as the speed stays very low.

The plugs are new and air filter is new as well.

I'm bald and if I had hair I would be pulling it out. I'm no mechanic by any means and have done searches here and on YouTube. I don't have a lot of mechanical knowledge but I have some neighbors who are very handy with motors and they seem to be puzzled as well.

Any thoughts???

Dom91

Sounds like the afm. I can't seem to find the thread but there's a really good write-up on testing it floating around.
Most have you test it when open and closed but it sounds like your having the same issue as a certain thread I can't find where it's from closed to open that the afm isnt functioning properly.
Do you have a friend with a 3.0? If so just swap his in real quick see if it changes

Jray215

Do you think that it should be replaced or can it be adjusted??? I've seen some mention of adjustments but have no clue.

Dom91

I'd just test it with the various ways there's write ups on it. Easiest way imho is just find a friend with one that's running good swap it in real quick see if your issue goes away

RJR

Before you take off the VAFM, try a few other things.
1) Make sure you have no diagnostic codes set. First, check to see that the check engine light is actually working, by turning the key to ON and observing if the lamp is lit. If it isn't, you need to fix that to determine if you have any diagnostic codes set.
2) To get the VAFM and the circuit opening relay (COR) out of the picture, jumper FP to B+ in the diag connector. That will bypass the COR and cause the fuel pump to run any time the key is on. If the problem goes away, the problem is in your VAFM/COR circuit, and you'll need to troubleshoot that. If it doesn't go away, it's a pretty good bet your VAFM is not the cause. (Regardless of results, don't drive permanently with the jumper in place. The COR is a safety feature to cut off fuel in case of an accident. The jumper defeats that safety feature and could result in a fire in the event of a crash.)

To be honest, the problem sounds like fuel delivery. You may have a failing fuel pump. There are ways to check the fuel pressure and delivery - search on this forum.

Jray215

RJR thanks for.the input I will try that in the next few days. I was kinda thinking it's a fuel issue as well. Hope to have good news soon.
Thanks!!!

Jray215

RJR the check engine light is working and not lit during vehicle operation. I put the jumper wire on like you suggested and the problem still continues. Here's what's funny. I can put the truck in low and it drives fine. Put it into second or drive and its dies in about 30 feet. What's that sound like????

RJR

Still sounds like fuel delivery isn't keeping up. It takes more power (and more fuel) to go faster. Will it go up a steep hill in low gear without dying? Or can you drive it in low with the brakes on w/o it dying? What happens if you rev it up to 4000 rpm in neutral - will it keep running smoothly or start sputtering?

Jray215

I can apply the brakes and give it gas and it does not die. I rev the engine to high rpms with no issue. A buddy of mine feels like it may be the crank sensor. He said he had a truck that was doing pretty much the same thing and it was his crank sensor.

VenomHilux

Did you find out what was your issue. My truck is doing the exact same thing. Runs idles drives in low but dies in all other gears. I’ve replaced fuel pump, fuel pressure regulator, plugs and wires, distributor, cap, and rotor, coil, tested igniter. I’ve been all over this truck. I’m missing something. But not sure. Did the crank sensor theory solve you issue?

Jray215

Turns out I had to finally take it to a buddy who has a small shop. He checked out everything he could think of and finally found a post online. Turns out it was a faulty ECU. Purchased one off rockauto plugged it up and it runs like a champ!!!! Now hes just fixing all the AC leaks and I will be back on the road soon. Hope this helps you out.

VenomHilux

I just replaced my ecm. And it runs great. Thank you for you thread and thank you for your response.