well i thought it might not be a vacuum leak beacause it comes and goes the problems is only present at start up and when i drive at low speed constantly like below 30

 

i sprayed 2 bottles of carb cleaner on the vacuum lines pvc valve and the egr as well as most of the other things on the vacuum diagram on my truck and then just sprayed it around on the motor but no change in the idle this morning when i started it up it did fine but i may go out this afternoon and it may not run hardly at all once it starts having the problem it only last about 30 sec to a couple of minutes and when it starts thats when i get the lean code when it is doing this i can spray carb cleaner in the K&N air intake and it quits and runs fine for a while

 

torkum - That's a good one.

DCannon2763 - Put that damn Carb Cleaner away for now. I know your new and welcome. Yea - post everything that's been done up to this point to fix or figure out the problem in your first post and most likely you won't be directed to the search bar. From now on.

You just wasted a little of our time here - I let yuh slide this time..torkum's the mean one with the chainsaw - I'm the nice guy

P0171 System Too Lean (Bank 1)

1. Disconnect BOTH sides of your battery.

2. Pull your PCV system, ALL of it- From the grommet in the valve cover to the 90 degree elbow that pugs into the manifold back by the firewall. The problem MOST of the time is in the PCV system lines.

I think you have developed a pin hole in the 90 degree elbow by the firewall - That's the weak spot in the system. Go thru all that and post back what you find. Make sure you have a Motorcraft replacement valve. Use the Motorcraft brand only for that.

Here's some more 98 pics - Pull the system OFF the truck.

The PCV System -




The elbow that goes bad is circled in red. Now the plastic hard-line can fracture as well. Your problem is intermittent at times and it's happening upon start right? The new IAC will act goofy with that kind of leak - specially after a cold start.

BTW - Carb cleaner is the worst thing you can use. It will melt rubber/plastic/bare the wires on your coils below. If you sprayed around your EGR valve - The diaphragm is prolly compromised.

When you pull the system, DO NOT pull the lines w/pinch clips in the pic above. They should be connected the the TB tree and have coolant in them. Pull the one off the Y connector @ the PCV valve, then push the 90 degree elbow off the stem by the firewall behind your IAC. Pull the PCV valve and the system will slide out of there.

Do what I said and post back.

 

Take a closer look at your CAI to be sure all the grommets are seated correctly.
Make sure that there are no leaks where the MAF attaches to the pipe. Check the lines going to the driver side cam cover. make sure that the IAC pipe is properly seated on the barbs at both ends.

Regards

Jean Marc Chartier

 

the elbow and the pcv valve were replaced about two months ago i use throttle body cleaner not carb cleaner i dont know if there is a difference but thats what i used i thank you guys for your help also i contacted the ford dealership and he said that only ford parts work and my o2 sensor is bad all four o2 sensors are new but he said only the ones from ford work is he just trying to make money??

 

Damnit! Now I'm p^ssed! I quit!

Crap!

Torkum might have a chainsaw , but I gottuh Hammer -

 

well sorry i made you mad thanks for your help

 

I doubt it - I gottuh rocket too -

 

Bosch make the O2 sensors for Ford. If you have installed Bosch sensors then you are fine. Check the CAI......

Regards

Jean Marc Chartier

 

3. Check the IAT grommet, those can split as well. Leave your O2's alone IF there OEM's - I would say there doing the job, but if you used other is a roll of the dice on what havoc that may cause.

4. Clean the MAF again.

5. Your intake gasket is leaking, most likely the lower towards the front water jackets. The heads pit there as-well. Use a propane bottle with a 3' section of hose to detect gasket leaks - passenger side.

Now if you did all that - I'm going to Nuk yuh -

 

I have a K&N cold air intake the groment in the middle of the pipe is kinda loose

 

Thinking I might have something wrong with my temp sensor...horrible fuel mileage...black tail pipe...and NO CODES. My belief is that the temp sensor is the ONLY thing that will not throw a code....is this correct?

Anyway, FWIW, 1999 5.4L Exped 4x4....168,000 miles and strong! (Just thirsty!)

Sam

 

The mechanic boogered our wiring harness and then routed it wrong. Too much tension at CHT and movement at other end. The temp gauge jumped and went to zero and the A/C stopped working. Not wanting to remove the intake manifold, I discovered that it was possible to get to it by removing the alternator and the insulation barrier around the manifold. I broke the insulation barrier at the corner to make it easier, then popped the two fasteners in the middle and pulled it out. In the back I had to pop the fuel rail off and up to get to the disconnect at the main Harness for the jumper harness. Could not find the jumper locally and the Ford dealer only had the full main harness. I got the jumper online@ usautoparts for $35 total including the shipping and tax. Piece of cake RR. Trouble shooting was a pain. 92k miles on the beast.