Have a new issue with my 2004 explorer XLT- long story-
I had decided to run Seafoam through the engine.
Disconnected the brake booster hose from the intake, installed a short hose and clean home made funnel. Note, i did not run the idle to 2000.
I poured in approx half a can, let the engine idle for a few seconds, and turned it off- waited 5 minutes and started the engine.
There was quite a bit of white smoke from the tail pipe, but then the check engine soon flashed several times.
i took the truck for gas and added almost the rest of the can to the tank.
now i get a P0316 and P0306.
i know the P0316 is a mis fire in 1000 revoultuions, and the misfire is in cylinder #6.
code scanner shows fuel pressure at about 40 PSI
could the application of the seafoam have caused this?
the truck ran fine before i added the seafoam, so i am looking for advise on where to look next
any ideas?

 

How quickly did you pour the SeaFoam in? Both of those codes point to cylinder number 6 since the P0316 stores with a companion cylinder misfire code. Certainly I'd suggest you start with a careful inspection. Remove the #6 spark plug and see how it looks. Does it appear to be firing, or is it wet with fuel or sludge? Maybe the SeaFoam broke loose so much carbon that the plug is fouled. Have you replaced the spark plugs recently? If the plugs are relatively new, you could try swapping the #6 plug for a different plug to see if the code follows the plug or remains on cylinder #6.

-Rod

 

Shorod, thanks for the quick response. I did pour it straight in from my home made funnel( old fuel filter with the top cut off).
I did pull the no. 6 plug ( driver side firewall) and it looks normal, slightly brown. I had rerplaced them about a year ago.
I will put a fuel gauge on the fuel rail and see what the pressure is. I have the old plugs- I will clean them and reinstall as a test.
Do you think possibily any sensors might have been damaged? The brake booster port is adjacent to another vacuum port- not sure which one..

 

Well you flooded the engine and catalyst with that crap and then added it to the fuel tank as well. I'm not surprised it threw a CEL. I'd just clear the codes and run it to try and get as much of that crap Seafoam out of system as possible. After the tank runs down a little top off with fresh gas to try and dillute the Seafoam. Use Chevron Techron next time. Seafoam isn't what some brag it up to be.

 

i did run the truck, even on the highway for a short distance, various speeds, still same.

 

The #6 plug wire is close to the area that you were working, check you have adequate spark to the plug... Philip

 

thanks for that tip- i will either switch wires with another cylinder ( this is a V6 or i will test for spark at the plug end.
i just filled it up with 93 octane (ouch) in the hope that it will dilute the sea foam in the tank. i may re do the sea foam treatment if all else fails.
I can here the misfire, sounds like a short but low rumble.

its too coincidental that the sea foam would cause a misfire, so i amhoping that this just an unlucky coincidence.
i will repost more info as i delve into this

 

Hey-
just wanted to post a follow up-
i replaced the existing Bosch Platnium plug with the old Motorcraft copper electrode type and all is well! the truck runs smoother and the mis fire is gone!! i took the truck on a highway run and no codes double bonus!!

apparently the existing spark plug was not firing, although physically it appeared ok.

Some of you like Seafoam, some do not- i am reserving judgement until i can run a few tankfulls and gat back to running on 87 as i normally do to see if there is any improvement.
So far, there was quite a bit of white smoke at the tail pipe, and i could smell the carbon that was burnt off, but i like to see tangible results and a noticble ingrease in MPG which was the reason for using Sea foam, as well as a dirty original fuel filter ( 86K miles)

Many thanks for the responses posted here- you have helped me narrow down the cause of this issue.
Sometimes, a difficult issue needs a simple cure........

Thanks again,
Michael

 

Ahhh, the Bosch strikes again. Several folks (magnitudes more than will bad mouth SeaFoam) will claim you're asking for trouble if you deviate from OEM style plugs in most modern engines. Personally, I've run in to issues when using multi-conductor platinum plugs, but have had great success with Iridium spark plugs.

I may be atypical though, because on the 7 vehicles I've used SeaFoam to decarbon, I've never once had a problem and in four of those vehicles I noticed a significant improvement in idle and power following the treatment.

-Rod

 

Yeah Bosch plugs. I wouldn't use them in my lawnmower. Autolite and Motorcraft plugs are very good and inexpensive, no reason not to use them.

 

This subject has been hashed over time and time again in the modular section. Motorcraft and Autolite are the only plugs to use. I would never use SeaFoam.