Most of the time when i start my truck it doesn't start normal and healthy. The RPMs dont jump up then go down like it should. the RPMS raise up slow and it starts slow and rough.

But, if i leave the key in the ON position for a few seconds, then start it, it makes an explosive big normal healthy start. But if i dont, it sort of eases into the start with the rpms low and it shakes the truck.

any ideas?

i just replaced the fuel filter within less than a year. and put all new plugs and COPS in it within the last six months.

01 4.6 with 180k on the clock

 

.Clean the throttle body and MAF

 

Thanks. Ill do that. Figured i should but didnt want to mess with it if it wasnt messed up.

forgot, i've cleaned the MAF within less than a year. Hopefully i can find that can of cleaner.

 

follow these instructions
http://www.fordf150.net/howto/throttlebodyclean.php
http://www.fordf150.net/howto/clean-...low-sensor.php

 

When was the fuel filter changed last?

 

in the last 6 months

 

Thinking there's might be a possible issue with the fuel pump/fuel delivery since you said if you leave the key on for a few seconds before you crank will fire right up. But definitely do all the cleaning items first whenever there's an issue. Replacing the fuel filter is based on miles, not time so if there's a lot of miles on that fuel filter or you suspect you may have gotten some dirty fuel, wouldn't be a bad idea to replace that if the cleanings don't fix the problem.

 

yeah thats what im really hoping is not the problem.
im going to try to clean the throttle body tomorrow. also clean the IAC and MAF while im in there

 

Change your FP relay.

 

that will be my next step! hopefully i wont have to go that far.

is there some sort of coolant line ill have to mess with to take the throttle body off?

 

FP relay is cheap and simple to change.

 

The TB is easy to get off and there's only 2 cables connected to it. The intake manifold (where the coolant line connects to) is another story (at least on the 5.4). When you pull off that coolant line, make sure the engine has cooled down so you can relieve any pressure from the radiator (unscrew the cap on the fill tank after it's cooled down) so when you disconnect the lines to the intake manifold it doesn't get all over the place.