My '00 5.4 has had a reoccurring issue w/the P1409/service engine soon light constantly coming on and off.

Recently I have had to start the truck and give it gas or else it would die out.
Now after starting, if I let off the gas, the engine dies.

I've changed the fuel filter recently. It made no effect.

any advice is appreciated!

thanks,
Steve

 

You should start be cleaning or replacing the IAC valve.

 

Since you have the 5.4 and a code my guess is that you have two problems both of which are very easy fixes.

as mentioned above low idle and stalling are almost exclusively related to a bad/clogged/malfunctioning IAC. Next time you have a low idle tap on the IAC with the handle of a screw driver and I bet your idle will go back to normal. Then clean or replace it!

Second very common issue is the PCV hose waaay in the back is prolly cracked or collapsing. it's the hose that attaches to the TB close to the fire wall.

 

P01419 is an EVR circuit failure. The ECU doesn't see the expected voltage drop. Check the connector, wires and the EVR solenoid...should be 40 ohms.

 

hcmq,

You were absolutely right!
After I tapped the IAC, the engine began running as it should.
I plan on removng it and cleaning it today.

My next question is:
I'm not sure exactly which hose is the PCV hose you spoke of.
Can you be more specific or provice a pic of its location?

thanks again!
Steve

 

follow the small hose that attached to your PCV valve and follow it towards the firewall and then right at the firewall it makes a u-turn and goes to the TB and connect right below the TB elbow.

it is a plastic cover on it and isn't always easy to tell if it's bad. Most times you will have to pull it off to look at it and it will either have a hole in it or it will collapse very easily.