My 99 4.0L has recently required more cranking to start then usual. I only notice this when the motor is cold. I have installed new plugs and a new pvc valve, also the wires are newer, and the air filter is good. Could this extended cranking time be related to the fuel system, perhaps a new fuel filter and an injector cleaning could be usesful?
Oh ya I have a 160000km or about 100000miles.
Am I on the right path? Thanks.

 

Do the fuel filter & injecter cleaning just because.
After that, if the problem still exists, you may want to check the fuel pressure with a guage to see if it is leaking down after the engine is shut off.
AL.

 

So if the leak down test indicates that it is loosing pressure -- what is the solution?

Mine is doing the same. I replace the fuel filter and ran some injector cleaner (techron) during a trip through the mountains. I reved the engine pretty good during the trip. I figured since most of my miles are in town that there might be some deposits. However, this morining it took a few seconds to start up. It is an intermittant problem so I dont think is is loosing pressure over night. However, I am still curious as to the solution.

 

Like Dealford sez, it might be a fuel pressure problem. Simple test: before starting turn the key to run for 2 seconds then off. Repeat 6 times then turn the key to start. If it fires right up, check the fuel pressure.

 

ok i'm pretty sure i'm losing fuel pressure as well after i shut off the engine what do we do to correct this problem?

 

Is it cranking slower?
try a new battery, esp. if it is worse during the cold.

 

mine's cranking fine in fact the battery and alternator are band new. I'm sure i'm losing fuel pressure but why and how do i fix that. I'd love to figure this out. thanks guys

 

have you replaced the fuel filter yet