Running poorly after seafoam

[Joe400]

I seafoam my truck (93 ranger 4.0) regularly about once every 5k miles or so. The last time, last week, I sucked it through the brake booster vac. line like I usually do, but I probably poured it in faster than usual. It ran rough like it usually does, and I shut it off and let it sit for a half hour. After I started it up, it did it's usually smoke-like-a-chimmney routine and I noticed the idle was still very rough.

Since then, the rough idle has improved slightly, but it fluctuates very quickly between 950 and 700 rpm. It sounds like it is misfiring on a cylinder or two every now and then.

The biggest problem, is when I am cruising about 30 mph, the engine bucks and jerks the truck back and forth, seemingly misfiring.

I pulled the plugs, they look fine (and are relatively new), I ran 2 tanks of injector cleaner through it, I checked for vac. leaks, and cleaned out the IAC and MAF sensors.


The truck has tons of power, it just runs rough at idle and bucks when at speed and under very little load.

Any suggestions??

 

[RyanD2]

I had very similar results when I used Seafoam, right down to the lack of power / bucking around 30 mph.

Took it to a shop and they found that all the buildup had basically been deposited into cylinder 3 causing a misfire.

Since you already checked the plugs I'm not sure what your next step should be. Is the CEL on at all?

 

[Joe400]

I checked the plugs and they looked okay, but thats not saying they aren't fouled/bad. The CEL is off, and never came on.. but hey, thats obd1 for ya..

what was the shop's solution for you? new spark plugs?

 

[Big Jim M]

My money is on at least ONE gunked plug. I'd be looking at them more closely. I might get one new plug and swap it around until I find where it does good..
Big JIm

 

[Downey]

you are suppose to change your plugs after you do it. go get 6 motorcraft plugs they arent expensive change them. i bet that will fix your problem. also why are you doing it ever 5k?

 

[TrexMex]

I have read elsewhere (can't remember exactly where) in the forum that Seafoam can mess up with the Oxy Sensors... have you scanned your engine yet?

 

[shadetree]

Why in the hell would you Seafoam every 5k miles????shady

 

[RyanD2]

what was the shop's solution for you? new spark plugs?

Yeah they changed cyl 3 and ran some injector cleaner through it and that helped the engine run normal again... for a while.

My CEL came back on but this time it was throwing Lean / Rich in bank 2 and after a lot of troubleshooting it came down to changing the O2 sensor. Havent had any issues since changing the sensor.

I was told by a lot of people that it was most likely a leak somewhere but I could never find one, even replaced the upper intake gaskets and bought a new IAC.

I can't say that your issue is due to your O2 sensor but it would be worth taking a look at least. But again... this is just my experience with Seafoam, and I'm not even sure the 2nd issue is related to using it.

 

[Joe400]

Why in the hell would you Seafoam every 5k miles????shady

I usually have a can or two kicking around between my car/truck and boat, so every other oil change or so I pour 1/4 to half can in. I've done it since I got the truck with 120,000 and now it has over 210XXX and runs beautiful.

Also, It turned out that the electrodes had completely melted off two of my bosch plugs. I have no idea why this happened.. the plugs were fairly new

I replaced them with new NGKs and it runs great.


Should have used the KISS method.