signs

Thank you to everyone who has giving me advice about what to look for to eliminate possibilities. I have posted several queries regarding a system too lean error, and although the information I have gotten from all of you is great. I still have the same problem. O2 sensors are new, iac is new, TPS is working fine, MAF is fine, pcv is fine,and the egr is ok.
My motor drives great, but acts like it is missing at an idle. Could this just simply be a clogged injector(s)? And what are some signs that you do have dirty injectors?

According to my manual you should check the spark plugs and wires
Then for vacuum leaks

new plugs, old wires, and what kind of manual do you have?

Its a 1980-96 Pickup and bronco from Haynes

it sounds like your egr valve is sticking open. take it off the manifold use a coke can to make a block off plate for the egr valve put it back on and see if the idle is ok.

I am not exactly sure what you mean by a block off plate. Please advise. And is there a way to check the egr? I assume that because there is flow through it, that it is ok. And how precise should the dimensions of the plate be?

just make a plate the same size as the gasket but with out the two center holes just the bolt holes. You can check it with a vacuum pump but only if its closing all the way at idle. block off the vacuum line going to the egr and put the pump on start it up and apply 10hg the engine will either idle real rough or die. the egr only works at cruise not idle or wide open. let me know

I'll give it a shot. Thanks Mike

well its not the egr or the regulator

Thank you to everyone who has giving me advice about what to look for to eliminate possibilities. I have posted several queries regarding a system too lean error, and although the information I have gotten from all of you is great. I still have the same problem. O2 sensors are new, iac is new, TPS is working fine, MAF is fine, pcv is fine,and the egr is ok.
My motor drives great, but acts like it is missing at an idle. Could this just simply be a clogged injector(s)? And what are some signs that you do have dirty injectors?

I would seriously consider changing the plug wires, I had a 95 dodge v10 truck with weak #5,7 wires. Once I changed them the truck ran great and had a normal idle. I could also feel it on the freeway at a stable speed like it was missing too. Good luck

The truck just seems to stumble at an idle once it is warm, and in gear. If i put it into park or neutral it comes right back. If it were a plug wire problem, which i am almost sure it is not wouldnt I get an error indicating a rich mixture

I had a similar problem with an '88 F150 with the inline 6. It eventually died and wouldn't start at all. It would crank over but wouldn't start. It ended up being the Ignition Control Module mounted on the distributor. Don't know if this is your problem but hopfully this will help some.

I'm not sure what year f-series you got, but the tritons have a vacuum elbow that goes into the back of the throttle body that was real bad about cracking and it'll throw 171/174 lean 1/2 codes.

To fordman:

thank you for your suggestion. I have a 2000 f150, and yet there is an ignition module, there is no distributor. there is now a cam sensor. I might as well check the resistance on the module anyway to make sure, but if it were the ignition module it would run very rough all the time.

To yotermanic:

I am getting p0171&174. I did a vacuum check at idle, and it held 20 in hg forever. and after a quick rev to 2500, vacuum went down to about 4"->25" then back to 20". Eveything that I know tells me that that is as good as it gets. But, If you or anyone else has more insight. Please fill me in. I am almost deperate enough to get rapped by a dealer to get this resolved.

I had a 5.4 in an expedition and it gave the too lean code. I had a ford mechanic buddy mention the elbow at the back of the intake like another reader suggested. I could actually hear mine leaking when I got close enough and could put my finger over the hole in it while running and the idle would smooth off perfectly. Hopefully you have checked for this. I replaced mine with hardware store parts instead of the $35 they wanted for a rubber elbow.