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03 3.1l po302 cylinder number 2 misfire

B

basimpo

New member
Hello all, my wife was driving and had the car stall twice on her. She brought it home and I pulled the engine code: P0302 engine cylinder #2 misfire.

I noticed our gas mileage has decreased dramatically.

Does anyone have an idea what I could look into to see about fixing this? Also, following the distributor wires im not sure which cylinder is which. The spark plugs seem buried if its in the rear but I got a picture for you. I want to say that #2 is the one in the middle, but I want to be sure before I start yanking random plugs.

Also, the second picture next to the oil dipstick is there because I cant figure out if that screw hole is supposed to be missing something or what.

Thank you!

Hm, I guess I cant add more than 140 something kbs of pictures hmmm
 

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On a 3100, cylinder 2 is the first one on the left hand side closest to the radiator.

So front bank is 2,4,6 and rear bank should be 1,3,5.

Cylinder 1 and 2 are next to the belt drive.


I would pull the spark plug and inspect it or just replace all of them and the wires if you know they have never been done.
 
Ok cool whew, kinda made me nervous to start pulling the engine around and everything. So, front furthest left spark plug, cool beans Ill take a look see and a pic too
 
The threads looked gunked up and kinda gritty but I dont really know about what a good/bad spark plug is supposed to look
 


The site wont let me upload another picture, ive hit the limit. The dude at autozone said that the plug was pretty burnt, I replaced the plug, cleared the code and ran the car. After about 5 minutes of driving the service engine soon light started flashing again.
 
You have to use a photo sharing website like photobucket to upload pictures, it's way easier.


If the misfire is still there on cylinder 2 after replacing that spark plug, swap plug wires around. Swap the 2 and 4 plug wires, they should be the same length or very close to it.

If after the swap of wires is done, and the say the misfire is still on cylinder 2, then swap coil packs themselves. Just don't mix out the plugs wires or it will not run right at all. I don't know of mechanically inclinded you are though.
 
Ahhh genius! Ok yeah I can swap stuff around. Ive youtubed fairly decently. The coil packs are in the picture that the wires hook up to, right? just unbolt and sling them over after i switch the wires right?
Easy day, Ill get back to you in a bit
 
Ok, replaced the wires, cleared the code. Misfire 2 still came up. Swapped distributor coils...so far nothing but I havnt drove it far yet. Switching the wires just idling for a few minutes with car in drive had it come on.
 
Ok more information. I just drove the car for about 15 miles, up and down hills, hard off of starts and easy off of starts and the SES light never came on after I swapped the distributor coil packs around. The car drives smoothly but idles roughly. My wife did let the car sit a month while I was gone at work and did not drive it. When i got back I jumped it and fueled it up. Ive noticed that its only got about 13 miles to the gallon when generally its been considerably more. Some people have suggested tossing some 95 octane fuel in it and some seafoam to clear the system. Any other suggestions? And thanks for taking the time to help!!
 


Ok so today I removed the thermostat and found that whoever owned this car previously apparently did not bother to tighten the lower thermostat housing bolt, and it seems that's where I was losing my coolant this whole time. Hopefully this solves my overheat issue.

Now about the misfire, it seems to only act up when the car is idle. It'll drive smooth, then randomly start to act up idling with the car in drive. In park idling nothing seems to go on. I've tapped on the injector leasing to number 2 with no difference. Any suggestions for the next step to take?
 
Misfires at idle (hi vacuum) are generally vacuum leaks. Think vacuum lines, intake gaskets, ETC..

Misfires under load or heavy acceptation are typically ignition. Think plugs, wires, coil packs etc....
 
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