I have recently been having a misfire code for cyclinder 5 on my 1997 chevy blazer 4WD 4.3 V6 engine. I notice it more when my vehicle is idling or at a stop sign. I have completely tuned it up, fuel filter, plugs, wires, rotor and cap, air filter. I ran 3 bottles of gum out injector cleaner in 3 tanks of 93 octane gas in hopes of maybe it was a clogged injector. This did not help at all so we ended up replacing two of the fuel injectors # 5 and then the clips broke on #3 and changed it also plus changed the ignition module. The service engine soon light will come on and then later go off, and will come back on again later. I dont understand why the code keeps reading misfire cyclinder 5, that is one of the fuel injectors that was replaced. If anyone has any ideas please do tell. It feels like the vehicle runs great going down the road it is only while idling or setting still at a stop light that I notice it the most. I am at a loss, They are going to try some type of cleaner in it that requires changing the oil and oil filter again. Any suggestions and/or advice would be very appreciated. I am running out of money to keep trying to narrow down the problem and this is my only way to and from work. PLEASE HELP!!

 

Hi, mine did at #2, had low coolant temerature, changed a thermostat, and my problem was solved!
At leastthis one!

 

I had a problem like this on a 97 chevy 1500 once. It doesn't sound like a fuel delivery problem it sounds like spark. Check and recheck your wire and make sure it doesn't have any damage to it. Then check the plug itself. My problem was the spark plug had a hair line crack through it causing a misfire. Sometimes at the auto parts store the plugs get dropped or what have not and can crack. Another common one is over tightening causing the ceramic to crack. Simple cheap test would be to put the old, or buy 1 new plug back into #5 and see if it changes anything.