1 Morning just started running rough (shutters on take off), 2 days prior fueled up ˝ tank. Not sure if it is a bad fuel problem because why 2 days latter. I pulled the throttle body off and cleaned it. It was heavily tarnished. I replaced the throttle position sensor. I pulled the plugs on the outer bank all are clean, very old but clean. I did not see any codes on the 3 cycle key. Check engine light flashes on certain speeds. What are the possibilities? Where should I start 1st ?

Thanks advance…

 

Check engine flashing is a very bad thing. It means there is a misfire bad enough to potentially damage the catalytic converter. I would start with the obvious and do plugs and wires since you said they were old. If you're over 100,000 miles and haven't replaced the O2 sensor, this would be a good time.
Since you are possibly linking this problem to bad gas, run a high grade injector cleaner such as Techron II or Seafoam through the system to see if that helps.
Until there is a code that is set, it's hard to narrow the problem down although I'm surprised that you don't find one since the MIL was flashing.

 

Do you tend to overfill. If you do, raw gas may be getting in the cannister intended for vapours, hence engine roughness. If so, should clear up in a matter of days.

 

Thanks for the feed back. Just got back from auto parts store, picked up wires, plugs & air filter along with 2 bottles of Seafoam. Letting engine cool now. There is a code P168.4 which means I think that the battery as been disconected within the last 50 starts. Also should I put both bottles of Seafoam in or one. I know what the directions say. Just curious if someone as a different Idea.

Again Thanks Advance

 

The ole P1684 code. It means there has been an electrical power loss, such as a battery disconnected, within the last 50 restarts. Make sense?

How old is your battery? Weird things happen when the battery is weak like dash gages going wacko and things, like wipers, operating without the switch being on. All do to inproper current flow as electronics and relays aren't powered properly (low current or dirty current).

 

Whelp problem solved, when I was replacing the plugs and wires I notice # 3 plug fouled, mfahey hit the nail on the head (miss fire). I also noticed #3 on coil side was arced. Still replaced wires and plugs. Ran veh. still runs rough. Went out and bought a new coil. And we are golden. Thanks all for all your help, much appreciated.

 

P1684 is a totally bogus code that shows up even if there has been no disruption in power. Just ignore it.