The 97 is going to the dealer on Monday, however I am fishing for opinions. On Friday, drove the car to town. On the way back, going up a long hill at 40 MPH, it begin to shudder and skip. I manually shifted to 2nd gear, and it leveled out, and ran fine the rest of the way to the house. On Friday night, the rest of the car pool and I started off for work on the interstate. The car was skipping on the exit, and the check engine light began flashing, then after a minute of so, it became solid. The skip got better as the engine warmed up, and there is no skip at idle, however under a load, a fine skip can be felt. The light has remained on since. My thinking is that a plug has failed, and the light was tripped by the o2 sensor. What do you all think? And yes, this is the car that is for sale. Who ever gets it will get a fresh tune-up as well. Thanks, Charles

Well, flashing CEL is a misfire. Check for coolant around any of the plugs, particularly around the ones closest to the t-stat. Others should chime in with other ideas.

Thanks, hadn't considered a moisture problem. I cleaned the engine about two weeks ago. Had better check to see if there is moisture in the any of the plug wells.

Flashing light is a misfire. If you can get it scanned and see what cylinder its happening on. OBD2 is great for things like this.

Check and make sure that all of your spark plug wires are "clicked" onto the spark plugs. If you have one that is just sitting on the plug and offers no resistance to being lifted that will probably be the one.

Thanks for the feedback. I will have to invest in one of those OBD2 things, as that will be handy. The wires are all snapped down tight. Everything is dry. No coolent leaks. I pulled the negative terminal off of the battery for a couple of minutes to reset the computer, and the light is staying off for now. The engine is running smoothly, except for a slight skip under load. It is going to the dealer this am. The plugs are the original, and the car has 102K miles, so it might be best to change them first, see what happens, then go onto the diagnostics if that does not work.

The shudder and skip going up a long hill your describing sounds like clogged catalytic converters.

yea grab the codes and if its fixable?? it will be fixed here thats for sure. codes are VIP.

Ford's service interval for the plugs on the 4.6 is 100k if I'm not mistaken. Probably wouldn't be a bad time to swap them out with some double plats. Just make sure the engine is cool before removing the plugs.

Let us know what those codes are, always helpful.

BTW, you don't have to buy one if you would rather not. Most auto parts stores will scan them for free.

The dealer checked it out and fixed it. It had a bad plug. They said that they could replace the bad one. I had them install a new set. Everything is operating normally. Drove it 50 miles this afternoon, and it is not setting any more codes. The car runs like a champ! Thanks for the tips. Sorry, they did not tell me the code number that it had set.