got this from the FAQ on the seafoam website take it for what it is worth......
I added a can of Sea Foam to about 12 gallons of gas in the tank of my 2002 Grand Marquis, then used ½ can of the spray in the intake. Now my car shows a “check engine” light that was not previously on. Did the Sea Foam somehow cause this? What should I do about it? Jim’s answer:Adding Sea Foam Spray Cleaner and Lube directly into the intake will, in some cases, trigger the “check engine” light due to misfires that occur while you’re spraying. The misfiring was only temporary, and you should be able to easily turn the light off by clearing the error code.
[Question asked by Tango Devin]