I posted a few days ago under "coil packs" about my truck misfiring. I replaced the plugs and cleaned out the spark plug holes and that problem and problem code have gone away. Now the truck has started running poorly again. The truck runs fine for 5 minutes or so (from cold engine) then starts stumbling intermittently like it is running out of fuel. Check engine light came on - code came up "lean condition on bank 1". I pulled the injectors to make sure they were not gummed up (truck has 105K) but they look fine. Also ran a bottle of injector cleaner through (hoping to get lucky). Check engine light has not come on again but I expect it will soon. I assume the fact that the lean condition is only on one side is a clue but not sure what it means. Also seems strange that the truck runs great when first started from cold. Any ideas out there?

 

The EGR valve does not start working until the engine warms up but I would think you would have p0401 or p0402 codes if it was EGR related. You could pull the vacuum hose off the egr valve and see if the stumbling goes away.

See P0171 - System Too Lean (Bank 1) at the following link and look in the possible causes column...

http://www.v8sho.com/SHO/TSB0197HO2SServiceTips.htm

Check all your vacuum hoses and make sure that they are in good condition and that the PCV valve etc. are where they belong. Its easy to move/remove those hoses when changeing spark plugs and forget to connect em back up. Another frequent complaint is that an elbow on the back of the plenum gets cracks in it over time and is one of the first things to check when vacuum leaks are suspected.

http://66.179.14.118/forums/showthre...uum+leak+elbow

http://66.179.14.118/forums/showthre...ht=p0171+elbow

http://66.179.14.118/forums/showthre...ht=p0171+elbow

 

P0171 is the code that came up last time. Would a defective oxygen sensor produce this code? I am wondering if running the engine for a few days with the ignition problem (misfire) could have damaged the O2 sensor. I have checked all my vacuum hoses but will do so again. I assumed a vacuum leak would affect the truck immediately when started. I also thought I could rule out a fuel delivery problem (bad pump, clogged filter) since the truck does not begin to stumble until it warms up. Thanks for the link.

 

hey, I wanted to chime in about my "engine stumble" (or rough idle) history.

Uh, I had a bad vacuum leak on the PCV valve hose ( on the end opposite the PCV valve ). You can check my post -- I tried to put pictures to explain what I was talking about.

Anyway, even with such a bad vacuum leak, the rough idle / stumble, did not start until after the truck had been running for a few minutes (when it had warmed up, I guess). Also, this was WAY in the back -- very hard to see. I found it by removing all the useless plastic cover things, climbing on top while the engine was running (carefully, oh so carefully), and listening to where the HISSSsssss was coming from. The "hiss" only started after the truck had been running awhile.

Oh, my leak was in that elbow that others have mentioned.

Good luck!

 

Elgallo,

Is this the hose you are talking about? It goes to the hole in the intake manifold.

 

I think that's the same one -- the one that still connected, right? Here are some pictures of my
leak and temporary patch that I had from a previous post

Here's some pictures:

TOP VIEW


SIDE VIEW

 

Yeah, the one thats still connected. I think we both have the same hose (PCV) but mine is the 5.4L and yours is the 4.6L. I just found out that I could click on your thumbnails and get larger images. Cool!

 

What about that Patch?!? Saran Wrap, Masking Tape, and cable tie! I thought it was pretty funny myself, but it actually worked. I just called the stealership -- they only want $28 for the whole replacement assembly, so I guess I'll get that and fix it correctly. I'm not looking forward to having to snake that hose through there.

 

Nice patch! Bet your hose is easier to install then mine...

Do you have to edit the URL/IMG stuff by hand to get the thumbnail to bring up the larger image?

 

You "nest" the img tags inside the url tags with the target "http" link inside the opening url tag,

like so:

{url=https://www.f150online.com/galleries/images/4168-6093-92345.jpg}{img}https://www.f150online.com/galleries...2345-thumb.jpg{/img}{/url}

Just change the curly braces to square brackets.

 

Nice, but you have to do it by hand. I thought I could just drop the thumbnail in here and it was all auto-magic but I know better now.

From one programmer to another, thanks for the trick.

 

No. Sorry. I guess I didn't answer your question. If you switch to the "Enhanced Mode" you can (1) click on "http://" button (2) paste in the full {IMG}http://link/to/thumb.gif{/IMG} in the text box (3) click ok (4) paste in the target URL of the full size image in the next text box (5) click OK. I'm not sure if you have to be in enhanced mode, but the above works for me.

To be honest, I usually just edit them by hand, though.

 

Thanks for the info and pics. It is quite possible that my assumptions have bitten me again. I will try to find the suspect hose this evening. I did push/pull the hose running to the passenger side valve cover around alot when I did the plugs and again when I pulled the injectors. Thanks again for all the help.

 

LayneT, what engine do you have again (4.6 or 5.4), what year, and how many miles?

 

Oh thanks Elgallo! The http:// button is just what the doctor ordered!