Ford 4.2 Misfire: Clean EGR Port via Seafoam?

Joined
Jan 29, 2012
Messages
675
Location
Canada
Hi guys, I'm trying to diagnose a 2006 Ford Freestar with the 4.2 of which the engine runs rough with a P0301 check engine light indicating a misfire on cylinder 1. Apparently this engine is known to have plugged EGR injection ports which require pulling off the intake to mechanically clean. To test if it was an EGR issue causing the misfire, I unplugged the vacuum line going to the EGR valve and miraculously the engine runs smooth. Before spending the effort pulling the whole intake manifold apart (it's alot of effort), I'm wondering if there would be any value in trying to inject Seafoam down the intake or vacuum line on the EGR valve? Would this knock off any of the carbon? Sorry if this is a noob question as I'm not that familiar with the EGR system. The intake manifold gaskets are also quite expensive, but they look like they should be reusable. Thanks!
 
Joined
Oct 16, 2019
Messages
150
Location
Texas
I think member BlueOvalFitter had this issue on his F150 4.2 when it was new back in 2007 or so. IIRC it was some sort of carbon buildup issue.
 
Joined
Mar 20, 2016
Messages
3,445
Location
Western S.C.
That seems to me unlikely to work, but I could be wrong. Keep us posted on progress. My Toyota is supposedly susceptible to the same problem--- along with carbon clogging of the EGR cooler (heat exchanger).
 

nobb

Thread starter
Joined
Jan 29, 2012
Messages
675
Location
Canada
Well, I decided to not half arse this and do it properly. I saw this video from FordTechMakuloco who suggested all you have to do is take off the upper intake manifold (on the Ford 3.8 and 4.2), then just clean out the EGR injection ports with a coathanger: https://www.youtube.com/watch?v=08IxhqpuQ3I I took off my upper intake manifold and to my surprise, there is no individual EGR injection ports as suggested in the video! If I follow the EGR valve, it seems to take the exhaust gas right behind the throttle body. However, upon further inspection it looks like one of the IMRC bushings for the linkage corresponding to the cylinder 1 bank of valves fell off. Not sure if this got knocked off when I pulled the intake manifold, or if this was the cause of my misfire. I guess I'll have to buy the part, put it all together and find out. It's just strange that the failed IMRC linkage controls the valves on cylinder 1, 2, 3, but my misfire is only on #1.
 
Joined
Dec 31, 2016
Messages
10,102
Location
Waco, TX
Originally Posted by bdcardinal
Those bushings are common. I force our system to keep a bunch of them in stock since they seem to sell in waves.
You are a walking Ford encyclopedia!
 
Joined
Jun 3, 2005
Messages
17,102
Location
Santa Barbara, CA
Originally Posted by Linctex
Originally Posted by bdcardinal
Those bushings are common. I force our system to keep a bunch of them in stock since they seem to sell in waves.
You are a walking Ford encyclopedia!
F5RZ-9F955-AB is your p/n for most of them. The 3V engines use different clips, but for yours that is the number.
 
Joined
Oct 3, 2010
Messages
2,294
Location
RI
The EGR system will not cause a single cylinder misfire. Does it miss all the time, under load, is the engine light flashing...?
 
Top