2005 Ford Ranger XLT 2.3 manual transmission with 140,000 miles.

The times when the truck has the issue are as follows. When the truck is warm and I shut it off and start it up 3 to 10 minutes later, the truck will start, idle rough for 2 to 5 seconds, then die. This has happened three times in the last week.

The first time the gas light was on (I was leaving to go to the gas station) and I was home so I added some gas and cycled the key a few times to prime the fuel system, started fine.

The second and third times I had lots of gas but tried the cycling the key a few times and again, the truck started fine.

This had me thinking the problem was a fuel pressure regulator. So I hooked up the fuel pressure gauge and pressures are good:
Key on - 60 psi
Engine running - 65 psi
Leak down very slow

The truck runs great when it starts, no drivability issues.

One other potentially related issue is that my fuel economy has taken a drop the two tanks. I check and record my mileage every tank. I initially attributed it to a drop in temperature but this is a more substantial drop than I'm used to. I average 27-29. The tank I filled last Thursday was 24.5 and the tank I filled yesterday was 22.8. I'm not convinced this is related, but just in case I thought it valuable to mention.

There are no engine codes.

Does anyone have any ideas on what to check next? I'm going to check/clean the idle air control valve this afternoon but I don't think that's it because in my experience they usually stick cold and not warm.

Thanks for any help.

 

Welcome to the forum

There should be no "leak down" in fuel pressure when engine/key is off.

At shut off, if pressure was 60psi then it should stay above 50psi for a few MONTHS, not minutes, hours, or days...........months

There is no fuel pressure regulator on Returnless fuel system, 1998 and up Rangers

At the end of the Fuel Rail there will be a Pulse Damper, it will have a vacuum hose attached for safety reasons, check that vacuum hose for fuel, shouldn't be any fuel or fuel smell, if there is then you found the leak and why MPG is dropping.

For MPG to drop the fuel has to be exiting the system without providing any power, so not a leaking check valve in the fuel pump, that fuel just goes back into the tank.

So either the fuel is being dumped into the engine, when it is off, leaking fuel injector or pulse damper, OR you have a fuel line leak.
Usually you will smell a fuel line leak, but in cold weather you may not.

Fuel pressure would be first stop, see if it is indeed not stabilizing and continues to drop.
If it is dropping check all fuel line connections first, fuel filter and at the fuel rail, feel connections with fingers and check for fuel smell.
Top of fuel tank is hard to get at and a fuel line can leak there but not a common problem.

 

Sorry, I am trying to delete this post. I will start my own thread.