LOL...here's the deal...I changed spark plugs today on my 2001 EB 5.4 It has 80,000 miles on it. I also changed the PCV valve. I used Autolite Platinum AP103 plugs, gapped them at .054 and torqued to 90 in. lbs. I did loosen and moved the driver's side fuel rail out of the way for easier access to the plugs. I put everything back together and took her for a test spin....and now I have a miss at 30-40 mph. It doesn't do it at idle, it starts fine, etc. What should I look for? Any one else ever have this happen....it didn't miss before......and the service engine light is not on.....Thanks

 

Does the 2001 have a coil on plug setup for each cylinder? If so, the boots on the coil will crack over time and start arcing causing a misfire (in my 2003 it feels like a buck or lurch).

 

Best to wait for that CEL to come on. It takes a lot of misfires to trip it. Try to keep it at that misfire range for a bit and that may trip it. Then have it read by your local auto parts store. That way you know which cylinder is misfiring so you can focus on that one instead of messing with all of them. I think your first problem was using Autolites. Most recommend only using original Motorcraft plugs in these engines because all spark plugs have different temp ranges and a lot have had bad luck with Autolites.

Another thing you can do is to pull all the electrical connections to each ignition coil and reseat all of them while you wiggle them. Sometimes its as simple as a bad connection. Im getting ready to change all my plugs (with Motorcraft) and COP's Thursday as well as clean the throttle body, IAC, and EGR. Mine is an 01 5.4L with 70,000 miles.

 

Thanks for the replies.....it has to be something simple. It ran fine before....I'll wait for the CEL and go from there.....that's good advice.

 

Yes...it does have COP setup....I replaced two boots that were iffy. I cleaned the rest and they looked fine. I'm thinking maybe a coil boot didn't get seated right. I'll wait for the CEL and pinpoint the problem.

 

I wouldn't wait for the CEL, you should be able to connect it to a code scanner (if you don't have one, Autozone will plug their's in for free) and see if it pulls a code. This happend to me once after I had cleaned the throttle body with CRC spray, one of the cylinders (I think it was #8) missed for a couple of minutes when I first started it up, so I shut it off immediately and connected my code reader and found the code for missing cylinder pop up. I reset it and cleared it, started it up again and it ran fine after that. Point is, I think you can still see a code come up for the missing cylinder without the CEL coming on, at least that's what mine did. Check it out with a scan tool and see if it indicates which cylinder, then pull that COP and plug and check them over; make sure you clean out all the crud at the top of the plug well where the COP meets the top lip and coat the COP top edge and bottom plug insert with dielectric grease, and make sure you 'feel' that COP spring completely seat on the plug as you push it back down into the plug well, the spring might not be all the way on the plug. Finally, check that the COP bolt is tight but only torqued to spec and no more. These are things that might help, but find out which cylinder is misfiring first.