So far I've been loving my Ranger pickup. Only issue I've had with it is a darn misfire I'm trying to get to go away. Here is a little history on what has been going on.

Bought Dec 14 with 142213miles on it. Dec 15 I got a check engine light and it felt like the motor was going to shake right outta the engine compartment. Ran a can of sea foam though the gas, and it smoothed out. Read the code Dec 17 (Monday), and got P0304 code. Cleaned it, and installed a set of Motorcraft SP432 plugs a couple days laster. Ran fine until Dec 21 (Friday) when I got another check engine light. It was missing, but not as bad as before. Drove 500 miles Christmas day, and still managed 23mpg. Just got my code reader tonight and scanned it again. Got code P0304, and P0306. Cleaned the light, and got a wire set on order that I will pick up, and install tomorrow night. When the truck is due for it's next oil change, I'm going to have them install a new fuel filter also. It has a new air filter already.

Any other suggestions to what might be causing the misfire?

 

when you gapped the plugs, what value did you use? i know when i did my plugs, there was 2 different gap values i found, the first was on the engine frame by the radiator, and the other was in the owners manual. the values were .062 and .054 respectively. when i used the .062 it was missing and pinging, however when i used the .054 value and it worked fine, my ping/missfire disappeared. hope this helps

 

Plugs were gap set at .044 and I found that information from ALL DATA from my work. The old Autolite single platnum plugs I pulled out of the truck were gapped at .048

 

When it is missing be very careful and pull cylinder 6 and 4's spark wire at the coil. If it sparks the coils good if not its bad. If the coil is good pull them at the spark plug and same thing. If it sparks its not an ignition problem. But most of the time it is. Fuel filter is a good idea, and id do it even if one of the wires or coil pack is bad.

 

Well I replaced the wires, and I'm still getting a P0304 code. Pulled the plug, and it's burning normal. The misfire only seems to happen at idle, and cruising speeds. Shakes the truck a little bit at speeds over 60mph.

 

Ok now my check gauge light is on when the truck is idling. I've checked all the gauges, and they all read normal except for my oil gauge. I've checked my oil level, and it's full. But the reading of the gauge is all messed up. When I bought the truck I noticed that the needle was below the peg that it would rest on the motor is off... So when you turn the truck on the needle hits that peg, and it won't read normal on the gauge. Would that have anything to do with the light being on at idle? Only happens at idle. During normal driving it doesn't come on. This has me so confused!

 

Hey, I had a similar problem, it is probably just a bad coil. Here is my trek through my similar problem:

Date: 1/21/2012 – 1/25/2012
Problem: Code P1151 (Heated O2 sensor—Bank 2, sensor 1, indicates lean);
Code P0301 (misfire Cyl. 1)
Possible Causes: P1151 – fuel system clogged
P0301 – bad plug, bad coil pack, fuel injector is clogged, bad wire;
Attempted Solution 1: New plug on cylinder 1 and fuel injector cleaner

Date: 3/4/2012
Problem: Codes P1151, P0301, P0303 (Misfire Cyl. 3)
Possible Causes: P1151 – clogged IAC, clogged MAF, bad O2 sensor
P0303 – bad plug, bad coil pack, fuel injector is clogged, bad wire
Attempted Solution 2: Did 60,000 mile maintenance, cleaned IAC and MAF

Date: 3/4/2012
Problem: Codes P1151, P0301, P0303
Attempted Solution 3: Replaced coil pack
Comment: Fixed

Ignition coil pack: $76.99 + $5.00 = $81.99

 

Installed new coil assembly, plugs, wires, flushed fuel system, cleaned MAF, changed oil, new filters all the way around. Still coming up with misfire codes no. 4, and no. 6 cyclinder. Also rough idle with flashing check engine light when engine is warm. Slight misfire felt when motor is under a full load. Cruising and acceleration aren't too bad.

Pretty sure I have the "bad valve" problem I keep reading about online.

I'm just going to run it until she don't run no more. Don't have the time or money to tear the top end apart, and replace heads.

 

Just ran codes again tonight and got the following.

P0304 cylinder 4 misfire
P0306 cylinder 6 misfire
P0175 bank 1 too rich

 

Replace the coil as stated earlier.
Put on the new wires and check the gaps again as suggested.

You ran the Sea Foam through it and that helped some, try Techron Fuel Injection Cleaner, it should help too.

Here is what I am talking about, Buy Chevron Techron Concentrate Fuel System Cleaner (20 oz.) 65740 at Advance Auto Parts.

They make a 12 gal version too !

 

I've done the sea-foam, Techron, and had the whole fuel system flushed by my local dealer aka my work.

New coil, new wires, new plugs, and I still have a rough running engine at idle.

Just did a compression test and I do have low compression on no. 4 cylinder. GrRRR!