I took my 98 to auto zone and I had about 8 codes, most of them having to do with the mix being too lean. At idle the engine acts like it is running out of gas, I replaced the EGR, Cleaned the MAF, replaced the fuel and air filters, I don't know where to go next IAC, oxygen? Help me please!

 

List the exact codes and tell us what engine you have.

 

I have the 5.4, I did not write down the exact codes but one was for the IAC valve, two were for the oxygen sensors bank 1 and bank 2 too lean, one was for the mass air flow too lean, and the thing is it actually smells like it is running really rich, I tested the throttle position sensor and it was fine.

 

I don't think there is codes for the IAC or the MAF directly, you need to go to auto zone and get them read and write them down. It's free.

Reason - certain codes will give good cause for others. Until we know all the codes , it's hard to diagnose..

This system exists to take away most of the guess work, go get the numbers if you want her fixed right

 

Fix your vacuum leak.

Start with checking the PCV hose elbow.

Large vacuum leaks can cause all sorts of symptoms including all the ones you've described.

Steve

 

I have code P0401 and P1504 and p1131 401 is insufficient EGR flow, i replaced the EGR valve, now I am going to replace the EGR solenoid. 1504 in an IAC malfunction so I am replacing that, 1131 is one of four that indicate lean. Would the EGR or IAC indicate lean and cause a rough IDLE, or do you think I should try something else? I am replacing these this afternoon so I will msg back and let you know how it goes.

 

Clean the MAF first , replace the air filter if dirty . Your MAF's prolly BLACK.

Your prolly going to need a DPFE sensor. You HAVE to get that from the dealership , don't buy one from a third party vender. Ford updated these and you need the updated one.

CLEAN that MAF first . Before you touch anything under the hood disconnect the battery , then clean your MAF good .. Reassemble your intake , then reconnect the battery and start.

Heres how you clean your MAF -

http://www.fordf150.net/howto/clean-...low-sensor.php

Your codes will go away except for the PO401, BUT, 401 won't come back until 3 or 4 drivecycles depending on cycle lengths. So when you get another Check Engine Light on - That's what it's going to be most likley.

Replace the DPFE like I described above.

 

give it a nice wet shot of nitrous that should fix the lean problem

 

I figured it out. I thought I had a vacuum leak but I couldnt find it. After replacing the EGR valve, The EGR vacuum solenoid, the Idle Air Control, cleaning the MAF, and changing the oil and fuel filter I found the problem. Under the IAC there is a vacuum hose connector with a formed bend in it. There was a rather large hole in it and when I pulled on it I ripped it right off, so the rubber was pretty rotten. I held the hose on there with my hand and the truck purred like a kitten. I now have to get some hose tommorow and make the repair.

 

yeh those damn Evap lines are a PITA. and always leave ur hands all black and chalky i replaced mine with a tranny fluid line

 

That sure sounds like the PCV hose elbow......

 

You were right thanks you must be a psycic

 

I thought you checked that , - POST 5.

 

Does the pcv valve hose have a outer cover on it?

 

wow, 3 years later.