Trouble shooting auto engine issues

Machine Repairs
1

Im looking for some advice from all you DIYers and mechanically inclined.

The other day i ran my truck down to empty on gas and the engine started to rough idle and threw some codes. I filled up and the issue resolved itself within 5 or so minutes after driving a bit, or so i thought. It didnt act up at all at highway speeds for the remainder of the 20 minute drive home.

I thought i might have had some water in the gas tank so i bought some ISO heat (water remover) and ran it on idle a few minutes in the driveway, no issues.

The next day i take my truck for a drive and at highway speeds, threw dome more codes and if i recall correctly had a rough feel to it at those speeds. Fluctuating RPMs and and idle very rough and shaking. Threw more codes.

I went straight to O’Reilly and got the codes checked. Only one, P0301, misfire in cylinder one. They suggested changing ignition coil(s) and spark plug.

Everyone else i have told the story to said “clogged fuel filter” which unfortunately is located inside the gas tank coupled with the fuel pump. Which sounds fairly obvious to me but im not sure now.

My question is why wouldnt it throw the P0300 (multiple/random misfires in different cylinders) if it is the fuel filter?

If it was just water, could that just ruin a spark plug or damage an ignition coil? Im not too familiar with the actual process so i dont want to assume or miss something.

Of note, cylinder one is blocked by the plenum? So that must be removed first to access the ignition coil/spark plug.

Any suggestions on first course of action to trouble shoot this issue? For my truck there are youtube videos on how to remove plenum/change all igniiton coils and also to drop the gas tank and swap fuel pumps.

I know i am competent enough to do both of those things but im wondering what i should do first or if any of you have first hand knowledge on issues i may run in to should i just bring it into a shop.

Any advice is greatly appreciated.

2

If you run gas down to empty, sometimes it can suck up any debris at the bottom of your tank, which could cause problems. I would change fuel filter first and go from there….if some debris got past the filter it could disturb fuel flow to one of the injectors too. Just a thought.

3

I would check the injectors. I had an ‘87 CRX I purchased used from a guy who had it sitting for quite some time. When I purchased it there was about 1/2 tank of fuel already in it. It wasn’t until I ran the fuel down and then filled up the tank that I noticed running issues. The crap that had been sitting in the tank was stirred up when I depleted nearly all the fuel in the tank as well as when I refilled it at the gas station. Fuel filter, fuel strainer in the tank, and two injectors later and I was back to normal.

4

Alright thanks, ill look in to changing the injectors as well.

Family mechanic said just change both the fuel pump.and ignition coils and be done with it. Didnt mention the injectors though. But while im at it…

5

Is the code always the same cylinder? If so, just swap coils around and see if your misfire moves with it. Simple way to check coil packs.

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6

So far yes only the one code/cylinder.

That was going to be my first choice of trouble shooting but the coil is blocked by the plenum so its a lot more work to just swap them. Once i get that far i might as well change them. I have the parts on hand.

7

Those coils will wreak havoc. Simple fix. But they are not cheap unfortunately. Like @Nickski said move them around to confirm or like your mechanic said swap it all and be done. Good luck. Vehicle problems are terrible

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just change that coil pack and plug, might as well since it’s a pain to get to. but also, what year make and model engine???

9

What kind of truck?

10

I’ve seen additives like that foul up 02 sensors and cause some really weird misfires.

11

i bet its a chevy.

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Actually its a 2006 nissan xterra. Hoping to ride her out until i need to upgrade to a work truck.

Im going to try all of the above this weekend, waiting on parts. Amazon prime shipping isnt what it use to be.

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13

hi . I have 2010 Nissan Frontier i believe it’s same engine. i was able to replace spark plugs without removing plenum. Hard bet possible, look youtube videos.

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Yes i saw that. Thst guy had all.kinds of rare tools to get into those tight spaces! Ill see what i can do with it.

15

Swapped the fuel pump, ignition coils, spark plugs, and the injector in the misfiring cylinder. It worked. The ultimate issue was unknown but all the work i did definitely was overdue anyway and now ive gained more experience with that type of issue and wont be as intimidated next time. Thanks to all who chimed in, i really appreciate it! Youtube is the real mvp in this one though :rofl:

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