Bucknut789

I got a 1993 F150 4.9 5 speed. The problem I am having is it will not start unless i give it a shot of starting fluid and then it will stay running but runs rough. Once it's hot it will restart. The last time I took it out it ran rough for about a half hour and then it started running perfect. Took it back home and then when it cooled down it goes back to not starting again. I changed the fuel filter and the pump is working good. I changed the cap rotor wires plugs. TPS,Map,Air flow sensors. Also changed the distributor and the coil. Fuel pressure regulator has vacuum and it wasn't wet when i pulled The hose off. The last thing I tried was I cranked the motor over enough that my plugs should have been wet but it wasn't when i pulled one. So it seems like I'm not getting fuel through my injectors when i try to start it but once it starts with starting fluid it stays running. I dont know what else to do. I have a spare engine I could pull the fuel rail and injectors off of and change it but don't want to do that if I'm missing something.

jmvc

i was having the same issues, i did the same you did, i notice that when the engine got hot, my truck would run really rough, it came to three thing, first EGR, then I moved over to the air flow sensor and what really did the difference was the fuel injectors, but for my case every time I replace something, my truck would run a bit better. I did changed the fuel pressure regulator. TPS sensor. I also cleaned my Air intake manifold and change the gaskets on it. I can tell the big difference on MPG and the smoothness on it too.

raski

You have done everything but did you actually measure the fuel pressure? .Sounds to me like you have a weak fuel pump. Unless you have done that, you don't know your pump is good. Just hearing it run means nothing. Your specs should be 45-60 psi at idle and a 50-60 psi rest pressure.

Bucknut789

UPDATE: Installed a new ECM on Saturday. Now the truck works perfectly. Thanks for your replies.