Stumped, Cylinder 5 misfire code
 

I have a cylinder 5 misfire code on my 98 Chevy blazer 4.3L 4x4. First things done were changing all the spark plugs since it hadnt been done for awhile. Most of the wires tore apart while removing them so they all got changed as well. The problem wasn't resolved so next I replaced the rotor and cap. While the symptoms of rough idle and nearly dieing at stop lights were lessened, they still weren't gone. I had my mechanics tell me based on the idle, engine code of random misfire, and black ring on the tail pipe they were pretty certain the injector spider was the culprit and needed to be replaced. It took me awhile to get time off to do it driving it in the sort of bad condition it was in.
I just barely got the spider replaced and though things feel better, I still have rough idle at low rpm, high rpm everything feels normal and back to a cylinder 5 misfire engine code. I'm stumped of where to go, what to do next. Any tips? Lost cause?
Thanks if you can help.

Sounds like your mechanics didn't do any diagnosis and simply wanted to throw an expensive part at the problem. The SWAG system. scientific wild *** guess.

If you are committing to obtaining the tools necessary and following instructions to do the required testing/repairs yourself, then we can get started with the diagnosis. But please don't waste my time if you easily discouraged or don't have the time. Your call. let me know.

What do you think Lesmyer, could it be he has a bad ignition coil? I have seen some of them go bad and they do weird stuff like this. Random misfires, misfires on one cylinder. That's just my two sense. Might be worth trying, they're pretty cheap on ebay and fairly easy to install.

Teal, you just failed Les's first test!:icon_laugh:

Naydog, Les can and will help you work the problem. BUT, you are going to do it the old fashioned way and earn it!! Maybe you are to young to remember those commercials... seriously though, search for Les's thread on his own engine and the thread where he helps Joe work through his misfire. Great background info to see what you are in for and see if you are up to the task first.

Good luck! You can can do this!!

I did a search on Lesmyer and found 249 pages of postings!!!
How do I find the one he did on his engine and the one he helped Joe with on his misfire problem?

I still have cylinder 1 misfire at idle but fine during driving. I suspect the fuel injector spider but would like further diagnoistic first.

Thanks

Here is Les's own engine saga...

https://blazerforum.com/forum/2nd-ge...g-valve-87514/

And here is Joe's. Joe's diligence puts most of us to shame!

https://blazerforum.com/forum/engine...rogress-90856/

Of course it could be lots of things, but Naydog has already unsuccessfully gone down the parts changing route. What we are trying to offer here is guidance in diagnostic testing. He can get the quick easy guesses for parts changing all over the Internet.

Hey thanks for the vote of confidence!

Ouch! I cringe a little when I read the engine saga thread. It sure was an expensive learning experience. I had some pretty strange ideas early on and Captain Hook helped me understand a lot. Hopefully I have learned a bit in the last couple of years, so read it with that in mind! p.s. the Blazer has been fantastic for over a year now!

Joe was great! An old guy (even older than me). Took the diagnostics through to the bitter end and verification of the true cause!

Update your old thread and we will see what can be done about that.

Yeh I gotya. I know diagnosing a problem like this can be very extensive. Just thought he might want to try one more cheap thing. Cheaper than buying some of the diagnosing it