Ford Expy wont idle

[Fleetwin]

EGO/HEGO's do typically fail to a lean condition. That is to prevent unburned fuel going into the Cat's.

The codes depend, somewhat, on the scanner. The Ford IDS (Integrated Diagnostic Scanner) can show fuel trims and you can manipulate them to verify a component issue. Most aftermarket scanners cannot. They can read codes but do not allow advanced diagnostics.

I think you have two issues here.

1. Cooked HEGO's.
2. Cooked Cat.(s).

(Vacuum leaks could have caused both of these)

With all that said, those parts are not that particularly expensive. You'll recoup the money on resale and make resale a heck of a lot easier with a smooth runner.

The 4.6 is a VERY durable engine. I see many, everyday, with 500K on them.

just sold an 05 F150 with 270,000 Miles on the clock. Ran like a watch. For that matter, the entire truck was still a completely reliable daily driver. I shouldn't have sold it. Rare truck. Short bed, reg. cab, 4X4.

 

[Fleetwin]

You've got two threads running here. Confusing all. Stick with one. Same question. I suggest this one. Full history.

http://forums.iboats.com/forum/other...2-sensor-gurus

 

[Fleetwin]

Concentrate on one thread.

 

[Harritwo]

Sublauxation
,

Back in 2000-2003 and maybe more years, Ford had an issue with the ECM having a bad ground and throwing random codes. Not sure if this is what you have going on but definitely worth checking.

 

[sublauxation]

Sorry about the 2 threads, I didn't want to lose some people who had an anti Ford bias as that thread dried up!

I want to make this come full circle though. I read a lot of forum threads where people had the same problem but dropped off as they figured out what the problem was, only they never posted what that fix was. I want this one to be more useful for any poor soul who comes across it though I'm not sure it will help.

Before bringing it to the shop I did my own smoke test and found small vacuum leaks at the EGR and a small one at the PCV valve hose. I also had a vacuum leak at the brake booster that I knew about. I fixed all 3 and it did run better but still wouldn't idle at all.

I paid the shop for diagnostics and graphing values from their computer. I got the codes on my own, the shop did confirm them.

The codes were 2195 and 2197 (lean condition bank 1 and bank 2, pre cat sensors).

The graph supposedly showed both O2 sensors reading rich with no fluctuation. That makes sense as it would cause a lean condition, but to my thinking it didn't line up with what the codes said. And to have 2 independent O2 sensors go bad on the same morning? Supposedly it also showed the MAF sensor reading properly and good fuel line pressure.

The mechanic gave me an estimate to replace both O2 sensors as he assured me it was the problem. I disagreed with his findings and he no longer likes me. He did listen though, and he has the advantage of being able to simply replace parts until some combo works, then return those that didn't help.

In the end the problem was the MAF sensor. They're not cheap! I was going to go to NAPA and look at a new one for comparison before I even started taking things apart but they didn't have one in stock. Had I been able to do that I would have immediately noticed that the resistor was obviously missing from mine and it would have saved me $120 in mostly bogus diagnositics.

Most importantly, she again purs like a kitten!

Lesson learned: buy the scan tool Bruce posted and just keep doing it all myself!

Thanks for all the hlep!

 

[Boomyal]

.....How about Boomyal?.......

Boom Ya'll! It was a nickname given to me before the age of the internet. Check out my avatar. I used to own a Gun Store.

Glad you got it sorted out. I have a 4.6 L 2006. I bought it a year and 3/4's ago with 123K on it. So far, no troubles.

Too bad you were not close by. I could use a Chiropractor.