Ok. So I had a plug kind of blow out the other day (2001 4.6l). So I took it to the shop and had them do the heli coil replacement. I just went and got it and it seemed to be driving fine. But then I got to a large hill. So I down shifted to 2nd and all of a sudden the truck started making a weird ticking/knocking noise and then started to misfire bad. Then my CEL light started to flash at me. So I scanned the code right there and it was P0305 (cylinder #5 misfire). I pulled over and let it idle and then the misfire and weird ticking noise stopped and it ran fine. So I continued to drive it and upon another big hill it happened again. It is very weird. I thought it my be an ignition coil for the misfire but the weird noise makes no sense to me.

Any thoughts or ideas are GREATLY appreciated! Thanks.

 

Heli coils are not a good fix. Go find a time-cert kit & fix it right.

 

What is that?

 

Nevermind. I looked it up.

 

I would check the connection of the COP to the plug before I got into the Heli Coil. If the plug were loose, I doubt that it would get better when you pulled over. Make sure your connection is clean and put a little di-electric grease on the plug connection. Also make sure the connection between the wire harness and the COP is clean. I am thinking that something got broke when they put in that Heli Coil and this is what is causing your problem.

 

But the #5 is on the other side of the #4 which is the one I had to get the heli coil done too. So why would that he a problem? Not arguing just trying to figure it out.

 

Sorry I miss understood thinking you put the Heli Coil in #5 Your problem is therefore a problem with your plug or COP. That is assuming that something didn't go bad like a valve in that cylinder. I would start by taking off the COP and inspecting it for obvious problems. also, pull the plug and if it looks bad, put in an new plug (I recommend only using Motorcraft plugs).

 

Yup. That's what I'm going to try tomorrow. Thanks for the help brotha man.

 

Did they reset the PCM after replacing the coil?

 

Maybe it’s time for a tune-up ??