Just in case it would help anyone else on here.. I had a problem a couple weeks ago and I think I've cleared it up.. or at least lessened the problem..
'96 mustang coupe automatic, 130,000 happy miles 3.8 liter engine.. Within 10 miles of getting gas (4 weeks ago) at a place that sells tons of gas I got a check engine light. I checked my gas cap, then plugged in my scanner (I carry it with me as .. it's small,, and I sometimes travel great distances from home) (engine ran great all through this problem) I got the code "P1151" Manufacturers control air fuel mixture. Checking the status of the various sensors would show 02 not ready, H02 not ready catalyst not ready. My repair manual didn't list "P1151" but a google on it showed a really big list of stuff to look at. It basically said that something is wrong somewhere between the water pump and the taillights. Resetting the codes with scanner, the error would come back within 15 miles of driving, always the same code, but sometimes one O2 sensor would be "ready" while the other wasn't. After hearing praises for Sea Foam here and from a mechanic friend of mine, I gave it a try. (the friend works on city equipment, police cars and other stuff, mostly high mileage and abused)
I didn't have any kind of pressure tank to feed Sea Foam into injector manifold. As per directions on can, I pulled vacuum line from brake booster, and as per advice from friend, pour 1/3 can in with engine running, then pour rapidly enough to flood the engine till it quits (vs instructions on can saying to shut car off) Allow car to sit for 5 - 10 minutes. Pour rest of can into the gas tank. Ran car and got it up to operating temperature.
Like I said,, I was getting that same code every 15 miles (distance to work).. I've now driven 400 miles without getting code. Checking sensors shows that 02 , H02 and catalyst are all happy,,,, for now anyway.. O2 sensors are original equipment... I could have needlessly changed them if it were not for doing this.. (oh yeah.. the 400 miles I've driven since doing this, have been same as during problem, 15 miles to work, 15 miles home..always being at operating temperature prior to hitting the road.. remote starts are great!) Chuck