Okay, I'm new to this site because I need some help. My truck fooled me into thinking I was out of gas in October, but that wasn't the problem. Since then it's been shaking a little on idle and really shaking around 45-55mph and a little at all the other speeds. The service-engine-soon light is on and blinks when I go up a large bridge in Corpus Christi, Tx. No power either. Also less gas mileage, but I don't care about that as much as the shaking and loss of power.

I soon found out that I had a cylinder misfiring and had my dad's friend who's a mechanic take a look. He tested it and the number 8 Cylinder was misfiring.

He said all we had to do was go and get a new coil pack and replace it and the problem would be solved. I felt great about it. So, that's what we did.

Right away, after installing the new coil pack, we tested it and no cylinders were misfiring, and the idle was back up over 700rpm or so and steady. I was feeling great now. We then took it around the block and drove it a little fast. Everything seemed fine when I left and paid the guy the 26 bucks I had on me. Thought it was well worth it.

Almost home less than a mile away and service-engine-soon light is back on and the truck is shuttering again. I dont' have much money and I was a bit ticked at spending around a hundred on something that didn't work.

I've looked through and read a few similar problems on this site, but haven't seen any that had the coil pack go bad right away and have all the problems go bad again.

What is happening? Is my coil pack being blown out right away after being replaced? How do I fix what is ruining my coil pack? Why would a different coil pack go out or a diff. cylinder missfire right after I fixed the new one? I just dont have the money to spend 500 or whatever it may be at a shop, I'd rather have this guy fix it for a few bucks. Please help, and thanks for your time, I know it's valuable.......................Rekshop02

 

What's to say it's the same coil that's bad? Stuff happens. Tote it down to Autozone and get the codes checked for free, see which cylinder (if different) is misfiring now.

 

Might also want to check that the COP harness did not pull apart somehow and that its plugged together firmly.

 

If one goes, usually others go too.

Adrianspeede

 

I just started having this same problem on my 2000 F150 approx 45000 miles. Took it to Firestone for the diagnostic. Didn't know Autozone would do it for free. Got the call saying one ignition coils was out and two more were intermittent. They want to charge me over $700 to replace the 3 coils plus the plugs on top of the $100 for the diagnostic. Said they'd do all 8 for around $1400. Figure I can do these on my own. What worries me is that I can play this game until I've replaced all 8 and the problem remains. Saw a thread of a guy that's done just this (and paid handsomely) and is still having issues. A suggestion was that it may be an issue with his fuel pump.

I don't mind paying $200 to fix the three coils and do it myself, but if more start to fail, I want to make sure that it's the coils that need replacing.

Also, anyone know of a good visual walk-through (or even text only) for the 4.6L V8. I haven't gotten it back from Firestone yet so am not sure how much disassembly will be required to get to the coils / plugs or what tools I may need.

 

I remember someone offered all 8 COPs for $200. Im to lazy to search right now but a search would probably find who it was or someone might remember who it was and post it in this thread again. Troyer maybe?

 

I believe those sold out a long time ago. He doesn't even show those on his site anymore.

 

many of the coils people defect are a result of just a bad boot. the boots are cheap and they are made by standard ignition SPP49. I think is the part number, or maybe onother company is making them by now. also make sure the plugs are not worn out or gapped too big. That requires the voltage to go up to jump the gap and weak plug wires/coil boots will fail when they might have lasted another plug change. fixed many in the shop with just boots, and a few with a coil or two.

 

I'd like to thank all y'all for the help on that. I'm still goin' paycheck to paycheck though, because I'm a 22 year old college dropout working construction, so it's tough to decide what to spend on. But I know a mechanic who can get me those coil packs for around 60 bucks and will basically help me for free. So should I try replacing the one, then test again if it shakes, and just replace them all? Is intermittance reffering to coil packs that will soon go out? I plan on doing the wires, plugs, and the #8 cylinder again and then testing afterward ofcourse. I'll check the boots and stuff too. Thanks again y'all..............Rekshop02

 

Take it to Autozone, get the codes pulled and see which cylinder is skipping before anything else. Then swap that coil with a known good and see if your misfire changes locations.