4runner has been driving a tad funny recently. acceleration seems a little weak, and exhaust sounds not as smooth, almost more like a go kart or something. so i pick up a can of seafoam, (i use one every oil change, have been for about 3 years) thinking that might help. i run half the can, shut the engine off, and it keeps running for about five seconds.

any thoughts? it scared the crap outa me.

 

carbon deposits in the cylinders? if deposits get hot enough it could act as the ignition source casing the engine to "diesel" after you shut the key off

 

x2 could be timing.

 

THIS /\

But its in the intake. Likely need to pull the intake and clean it out really well. Something is clogged. You are likely getting a lot of blow-by and the intake is full of sludge and crap.

IMO, Seafoam is not supposed to be used the way you are using it. Only use it every few oil changes and only for the last 100 miles before you change the oil. It breaks loose deposits, but then those deposits float around inside the motor as long as you run it. So, the oil needs to be drained out to get them out. My guess is that the seafoam has now caused the issue you are having. Things need to be cleaned out. Or your motor is going to be toast.

 

When I used seafoam before, it fouled my spark plugs. Check that too.

 

Are you due for a tune up?