I have a 1997 F150 with a 4.6. I changed the plugs and wires, but get a engine code that says misfire cyl. 8. The coil is firing on the No. 8 position, but the truck still runs rough and the check engine light flashes from time to time while driving. Is there something else that could be giving me this code besides a misfire. Any info on this matter would be helpful.

 

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I recently got a code p304 on my number four cyclinder. Found out that the wire was rubbing a moving part damaging it. Replaced and that took care of it.

 

I had the same problem on my 4.2 and the cylinder was firing at the coil, but we replaced it anyway and that fixed it. Weak coil.

 

Same problem here.The coil was the problem.

 

I have a 97 4.6 also. changed the plugs and wires and coil packs. It drove good for a year and it started doing it again a couple weeks ago. Took it to A- Zone and #3 misfire. I got looking around and the clip to my #3 fuel injector had a broken clip. I tried to rig it. But it might need to be replaced. Also if you have a K@N filter it will clog up your MAFS, and possibly have the same problems.

 

I have a K&N air filter as well. What is a MAF??
Also, my truck shakes , more when accelerating and lightly when sitting still. Should I just a get a new air filter and what would you recommend?

 

Mass Air Flow Sensor. Measures the airflow going to the trhottle body. Many users of oiled filters tend to over-oil the filter when servicing it and the excess oil fouls the sensor causing problems. Your symptoms are not among them.

You have a misfire. An air filter is not going to help it. If your CEL is on or flashing, get your codes read and see which cylinder(s) is causing the misfire. The vast majority of misfires are due to plugs, wires, COPS, or coils depending on which system is in your engine. Occasionally, misfires will be due to injectors or valve problems, but the other causes are extremely common.

Steve

 

Run a can of fuel injector cleaner with about half a tank of gas and reset the cel.

 

Fuel injector cleaner will have no effect on faulty plugs, wires, and coils.

Plus, the stuff in auto parts stores isn't very likely to have any measureable effect on the fuel system. Most fuels sold today have a very robust additive pack that makes most injector cleaners unneeded anyway.

Steve

 

I didn't say it would. Thats why it's called fuel injector cleaner. It fixed the exact problem described above only on 99 explorer with 4.0.