elkhunterman

I have a 1999 F 150 with 75,000 miles on it. I have owned the truck for a little bit over a year and it started to act up when I'm starting it cold. the motor cranks but doesn't want to fire and the problem is getting worse. I change the plugs and fuel filter when I purchased the truck and have been mixing injector cleaner in with my fuel. any ideas what is causing this?


oh and by the way I'm located in Arizona so the winter temperatures are not to extreme. I'm thinking that it was just a coincidence that it started happening when it started getting colder.

elkhunterman

oh and the motor is a 4.2

akdoggie

Have you checked the fuel pump? When you turn on the key, can you hear the pump in the tank pressure up?

You can check on the fuel rail. There is only 1 of these on only 1 rail. There is an oversized valve there. It looks like a big truck tire fill stem. Take the cap off, and press the little button inside and (be careful as it will spray everywhere if you have pressure) see if there is fuel in the rail. It will spray everywhere when it's pressurized. It will dribble if the pressure is low or none. If it has pressure, then you would go to step 2.

Check the spark at the plugs. (You can remove one wire from a plug and see if it sparks when its grounded out). If it sparks good, then to next thing. Let's get to that after we do 1 and if necessary 2. Good luck

elkhunterman

the fuel pump and spark plugs seem to be just fine. the truck runs great after it finally start. but before it finally start it just wants to crank.

akdoggie

Check the fuel pressure valve on the rail. It has the single vacuum hose running to it. Either pull it off the valve, or clamp the hose off and see if that helps it start. If so you may have a bad fuel pressure regulator, causing the problem. Those usually won't show up on the OBD II reader, or set a hard code, but can make cold start a real biatch. Check the AIC motor also. If it is hanging up, due to the colder air, it can make starting difficult. It seems a lot of guys lately have experience that problem. It goes with cold weather and aluminum parts. They don't like each other very much.

That could be your simple fix to a simple problem. Or Not. lol Good luck.

elkhunterman

I checked the fuel pressure on the fuel rail and it seems great. sprays out a lot when key is turned. do you think it could be Electrical timing? I think if I had fuel pump failure that it would run rough when I floored it while driving

akdoggie

You have cam and crank sensors to operate the firing. I wonder if one of those might be bad or dirty so it doesn't read right? That should set a code though. I'm at a loss if you have fuel and spark, you should have a running motor. You do have good spark right?