I have been reading the threads on the 4.6l misfire. On my 98, all of the symptoms are the same here. I get shudder mostly when I reach 40 and above. Idles great. Had the codes checked at Autozone and get the 302 cylinder 2 misfire. I changed plugs and wires and continued to get shudder. Thought possible transmission problem until I got the CEL again. Took it to the dealer and they got the same 302 misfire code. They switched the no. 2 cylinder wire with another wire to a different cylinder. Drove it home misfiring all the way. Took it to Autozone to read the code 302 cylinder 2 misfire. Now with a different wire on cylinder 2 and I am getting the same code, it can't be the wire. Could it be coil pack? What else would make just cylinder 2 misfire?

 

Does it just misfire under load or all of the time? If it just under load then it is most likely in ignition, like coil pack. If it is all of the time then I would look towards an injector.

 

It bucks and shudders under load. It idles just fine. Only when I give it a little gas as you start down the road or already on the road at cruising speed do you start feeling the shuddering and hesitating. I agree that it sounds like the coil pack. I got a quote from Auto Zone for their coil pack for $40.00. I got a quote from Ford for a Motorcraft coil pack at $129.00. Does anyone recommend a particular manufacturer for a coil pack?

 

i have a 97 with a 4.6 and i had the same problem however with just cylinder one. i knew that it couldn't be the plugs and wires because i had replaced those just 4,000 miles ago. i pulled the plug to look it over anyway and it looked fine but i re-gapped it for ****s and giggles. it still idles fine but as soon as i gave the least bit of throttle it was very rough and shook the whole truck. i then topped the tank off with 93 octane and dumped in a bottle of superconcentrated fuel injector cleaner. halfway through the tank it wasn't getting back to normal however it felt a little better. i decided another bottle wouldn't hurt it and i topped it off with 93 again. now i am halfway through that tank and it runs fine. i suggest you just get it drunk on injector cleaner and it should fix it. good luck.

 

I had a similar problem with my 4.6. Check out my post a couple of months ago https://www.f150online.com/forums/sh...threadid=85603

It is still running like new, too.

It was the voltage that was high on the TPS.

Here is one post from me...

Here is a summary of what was done:
1. Check all fuses and o2 sensor (NC labor)
2. Replace plugs (8 @ $4, 1 hour labor)
3. Replace plug wires (Beldin lifetime warranty $112.98, 1.3 hours labor)
4. Replace TPS and CTS (high voltage) (TPS $59.95, CTS $28.10) (1 hour labor)
5. Scanner & trouble shoot (NC labor)
6. Compression check (0.4 hour labor)
7. Clean injectors ($12 machine, .4 labor)
8. Tighten and clean all injector harnesses (NC labor)
9. Check EGR valve, throttle body, gaskets and vacuum system (NC labor)

Total for parts, labor and tax = $520.64

 

if you end up getting coil packs get the MSD ones much nicer than stock... ...coil packs fixed my misfire.......

 

Well, I put a new coil pack on the side where the misfire was coming from (driver's side). The misfire was definitely the coil pack. No more misfiring. I got a Motorcraft coil pack from 1stfordparts.com at about half of what the local Ford dealer wanted. Thanks to everyone who replied.

 

Thanks for many of your input. I was able to solve my misfire problem. I had one misfire code 303, changed all the spark plugs, problem went away for a week and came back, same code. I check the plug wire, had a good reading comparable to other plug wires. I then lifted the fuel rail to swap the #2 and #3 injectors. After that, problem did not go away. Next I tried to swap #3 and #7 spark plug wires, this time the misfire occur with a code 307. Now I knew it's the spark plug wire. Got a net set of Belkin with lifetime warranty from NAPA, changed the wires and problem has not come back. I was surprise that the resistance test of the spark plug wire did not detact the problem. Since the misfire could be electrical or fuel related, I'd suggest other owners to try the no cost methods first. Try swapping plug wires, left and right coil packs, and injectors before changing parts.

 

I too was misfiring. It was the coil. Thanks for the posts everybody.