I have a "cylinder one misfire" on OBD-II

Its a 95, 4 cylinder, 2.7 liter. I'm assuming #1 cylinder is the one in front (closest to me when I look under hood). Any advice?

 

start with the basics, pull the plugs and see what condition they are in.

 

Hey, thanks for both replies! That is my plan of attack. Knowing "Cylinder #1" is up front, now, should short-cut the process.

 

Okay, thanks for the previous help, folks. Replaced #1 cylinder wire and plug (will replace all four - thinking it can't hurt). Reset computer with OBD-II; engine light came back on within a few miles. Thinking I will replace distributor cap and rotor next. Any thoughts?

 

It would be wise to do this before you throw any more money at it.

 

Both sources of advice sound wise, thank you! I checked out the distributor cap, and my novice eyes don't seem to detect much - little bit of white and burn marks on posts. I'm supposing #1 post could be worn enough to cause misfire! I'm also thinking that, if it was the rotor, the misfire would be on more than one cylinder? Throwing a new cap on doesn't seem too ominous to me, but beyond that...

 

Okay, it has been two weeks. Replaced #1 wire and #1 plug. Deleted OBD code, but engine light came back on. Replaced remaining plugs and wires, distributor cap and rotor. Deleted OBD code, but engine light came on again. Filled gas tank, adding Seafoam, but didn't reset OBD codes. And this morning, engine light was off!! Any help in understanding how this happened?

 

Although I personally think Seafoam is snake oil, a dirty injector can give you a misfire code. Maybe the Seafoam cleared the injector.

I had the same problem (actually P0302) with my '02 Frontier. Completely refreshed the ignition, did a compression and leakdown test (both OK) and replaced the #2 injector. Still had the problem, so I sold the truck to local used car dealer, and he sold it at auction. Then I bought the new Tacoma.

FYI, after I sold the Frontier, a tech posted on one of the Nissan message boards that the lines that carry the EGR gasses to each intake port can become clogged, and cause either a lean condition (one line clogged) or a rich condition (3 lines clogged) either of which can cause a misfire.

 

Good to know, thanks. I was actually trying to understand if, maybe, I fixed the problem with one of my other DIY's (plugs, wires, distrib.,etc.) but that it takes a while for the engine light to go off permanently after resetting with the OBD-2.
I'm kinda with you on the Seafoam issue, though I don't think it hurts.

 

i had this problem when i was driving through water up to my hood all day and i sucked up alot of water and fried some very important wires, mine was a 99 tacoma v6 tho. good luck!