Well I finally got tired of having the hesitation problem at about 1500 RPM and also the fact that my Check Engine Light came on didn't help. I went out and got an OBDII and I'm getting a reading of P0401 EGR insufficient recirculation and a P0174 Running Too Lean on Bank 2 problem. The truck is really struggling now. It feels like it works way too hard to get going.

I have read that I may have clogged EGR ports and to remove the Throttle body and clear out all the carbon build up.

Could that be whats causing the Too Lean problem also?

Any help would be appreciated.

I originally thought it was a Spark Plug issue, at least that's what the dealer said, but I guess they're not sure either at this point. This all started when I swapped out the plugs at 65K...I know have 140K on it and aside from that the truck has been great just not much power anymore. By using higher octane fuel I have managed to eliminate some of the hesitation problem, but it's still noticeable.

 

From reading other posts it appears that I may have an EGR port problem. I'm going to start with that and see what happens.

 

Clean the EGR ports first, be prepared to replace the DPFE sensor if the P0401 comes back.

Check your PCV hose, especially the elbow all the way back next to the firewall.


Steve

 

Also, clean MAF sensor w/ Electrical parts cleaner. New plugs, no BOSCH plugs.

 

I ended up replacing both. I took the EGR valve off and it had some carbon build up, but since I have no idea what a really bad one looks like I just went ahead and replaced it. I didn't think it was too bad so I figured I was replace the DPFE sensor as well especially since I have over 140K miles on it.

I erased the codes and I have now driven about 35 miles or so and it's still clear, along with it running much better.

 

I've always had problems with plugs. Once I went back to using higher octane fuel the hesitation at 1500 RPM seems to have gone away.

What are the exact plugs that should be used on these 4.2L engines.

 

I read where Ford voids the warantee on throttle bodies if you use the wrong cleaner. They say that there is a coating they put in it to help prevent carbon buildup, and carb cleaners and such will destroy the coating.

With that said, does anyone have a recommended cleaning procedure to offer?

 

regarding plugs, here are a few old threads to look at.
I changed the plugs in my '05 about 3 months ago.
I got the motorcraft "FWP" which is Fine Wire Platinum.

Don't remember the number but I believe I could find it at home.

https://www.ford-trucks.com/forums/5...ht=spark+plugs

https://www.ford-trucks.com/forums/4...ht=spark+plugs

https://www.ford-trucks.com/forums/4...ht=spark+plugs


regarding cleaning the TB. Check your local parts place. There are spray cleaners made for teflon coated (interior) TBs. I have used them in the past and had no ill effects.
I think the one I use is made by CRC.

Thanks.

 

OK, I don't mean to sound preachy, but don't forget to check your vaccum lines. If you have a vaccum leak you will get a P0401 when the vehicle warms up because there is no EGR flow.

There is a vaccum line that goes from the EGR valve to the EGR regulator, this should be the "green" line.

There is a while line that goes all the way from the EGR regulator to a union of 3 vaccum lines behind the battery. This is the line that many miss and it does break. You will need to remove the battery to check this line.

The Vaccum lines are rigid plastic and when they get hot, they get very brittle and break. Disconnect the lines and use a vaccum tester to check for leaks. If either line does not hold a vaccum, there is your problem.

Good luck.

Vincent

Good luck.

 

Thanks Brian, I found CRC throttle body spray cleaner and CRC mass air flow sensor spray cleaner at advance auto parts.

I also used the MAF cleaner on the DPFE, seemed to me like it should be safe on that too.

I also found that to remove the MAF which is inside the air intake of the 4.2 you need a Torx #20 safety.

I removed the EGR valve and cleaned it with the throttle body cleaner, then I sprayed a little bit of WD40 on the moving parts of the valve stem and used a pair of needle nose to move the stem and excercise the diaphragm to make sure it operated smoothly.

 

After all previous attemps failed to clear the codes, I found TSB 04-11-01 which said that it might just be a malfunctioning DPFE. Replacing it cured all.
It looks as though the 401 was causing the 171 and 174 because all codes are cleared now.

DRIVEABILITY - STREAMLINED DIAGNOSTIC PROCEDURE FOR VEHICLES WITH MIL ON AND DTCS P0401, P0402, P1400 OR P1401 - ADDITIONAL SYMPTOMS MAY INCLUDE RUNS ROUGH, LACKS POWER, SURGE, POOR FUEL ECONOMY

<TABLE border=0><TBODY><TR><TD width=230>FORD:
</TD><TD>2000-2002 TAURUS
2001-2002 CROWN VICTORIA, FOCUS, MUSTANG
2001 EXPLORER USPS
2001-2002 E-SERIES, ESCAPE, EXPEDITION, EXPLORER SPORT TRAC, EXPLORER SPORT, F-150, RANGER, WINDSTAR
2002-2003 EXPLORER</TD></TR><TR><TD width=230>LINCOLN:
</TD><TD>2001-2002 TOWN CAR</TD></TR><TR><TD width=230>MERCURY:
</TD><TD>2000-2002 SABLE
2001-2002 COUGAR, GRAND MARQUIS
2002-2003 MOUNTAINEER</TD></TR></TBODY></TABLE>

This article supersedes TSB 04-3-1 to update service part information and applications.

ISSUE:
Some vehicles may exhibit a malfunction indicator lamp (MIL) "ON" with or without the following symptoms: Rough Running, Lack of Power, Surge or Poor Fuel Economy, along with diagnostic trouble codes (DTC's) P0401, P0402, P1400 or P1401. This may be caused by an intermittently functioning tube-mounted delta pressure feedback EGR (DPFE) sensor (Figure 1).

ACTION:
For vehicles equipped with a tube-mounted DPFE sensor, perform the following diagnostic procedure and repair action. This procedure supersedes the diagnostic procedure in the PC/ED Manual for the issue described above.

NOTE:
ALL LISTED APPLICATIONS CAN NOW BE SERVICED WITH DPFE SENSOR 4U7Z-9J460-AA

 

DPFE diagram: