I have a 98 e-150 with 202,000 miles. It has never given me any trouble until now. I get a code telling me #6 cylinder is not firing. I have new plugs and wires, coil pack, fuel filter, and have had the injectors checked at the dealer. They can't tell me what is wrong. It seems to run well except sometimes at low rpm it will hesitate a bit. Does anyone has any ideas as to what could be causing this condition. Thanks

 

Hi and welcome to FTE

I would check for a vacuum leak somewhere ans maybe try cleaning the MASS-AIR sensor.
By the way, what engine do you have?

Jimmy

 

Sorry, I have a 4.2 6-cylinder

 

Has it lost any coolant? Do you have to add much?
I would start with cleaning the mass air first. If it is dirty, it will not properly measure the air flow and will cause a lean condition that could cause a misfire.
Jimmy

 

Jimmy, Thanks for your responses. It doesn't use any coolant. I will clean the sensor in the morning and post the results.

Thanks
Jeff

 

Good luck to ya.
Jimmy

 

Clean sensor, still throwing misfire code. Would a bad injector cause this, or would it have it's own code??

 

If it is clogged it could. It may still be opening and closing, but not spraying any fuel. If it was the electrical part of the injector, it should have it's own code.
Jimmy

 

post this in the 4.2 forum we might be able to help you out there. thanks
Jimmy D

 

Jimmy - My 97 F150 4.6L is throwing the P0303 code for a cylinder #3 misfire. I plan to start with the plug and the wires. However, your questions about the coolant caught my interest. My has lost some coolant. I was wondering why you asked that question.

Thanks,
Tony

 

Go to the 4.2 forum, do a search for leaking fords. that should give you an answer, I do not know the link.

 

Hi acwalker and welcome to FTE

A 4.6 doesnt usually have head gasket problems to worry about. I'd have the cooling system pressure tested to see if you can find a leak.
If your plugs and wires have been in the truck for any length of time I think they are a good place to start to cure the miss.

 

You might check the heater hoses on the 4.6. They had problems with them leaking onto the engine near the firewall. They usually mess with cylinder #4, but it could be getting into #3 I guess.
Jimmy

 

Hey everyone. New here but I am having the same problem with #6 misfiring. I am trying to save $ by fixing it myself, but after tackling the plugs I'm not so sure. I changed the plugs but the problem is still there. Is the next step the plug wires and if that does not fix it the coil pack? The fault code is 306 #6 cylinder misfire. Or is there some way to determine exactly where the problem is.

 

Oh, I guess I should note that I have a 1998 F150 4X4 Ext Cab with the 4.6L Triton.

Thanks