per request I replaced the cap and rotor with ACDelco parts to no avail. I bought the whole spider injector from the junk yard and noticed that 2 of the injectors were new, so I took one of them out and replaced it with cylinder one. Nothing changed, same misfire code. I'm at a bigger loss now, idk what to do? I used a spark test tool as well on cylinder one and it showed spark. Any other ideas?

 

Okay, so you replaced the distributor cap and rotor with AC Delco brand parts. But what about the spark plugs? I had a similar problem just a couple of weeks ago until I switched out the Autolite Platinums I put in the truck when I bought it with AC Delco Iridium spark plugs (part number 41-993; make sure they are gapped to .060!). What do your spark plugs look like? Have you taken them out recently to inspect them? And, what brand plug wires did you use? Autolite Professional Series Ignition Wire set is what was recommend to me by a professional mechanic. They are just as good as Ac Delco brand but at about the 1/3 the cost.

Look, as everyone said already (and I didn't believe it either until I wasted too much money myself) but these trucks are very picky. I have never seen this before but it just seems to be true. At least, it's been this way for me. Sure, not all of my problems are fixed, yet, but I'm getting there.

How's your idle? Smooth? Rough? How does the engine run at different RPM's? Smooth all the way through the RPM range? Or, rough at different times?

 

This guy doesn't want to hear about AC DELCO parts read the post he posted responding to me when I suggested what you did.

 

You maybe right but I thought I'd give it a try. Besides, I was a true skeptic myself. I have never owned such a picky vehicle in my life! It just seemed too crazy to me. Oh, well, you live, you learn - hopefully.

Craig84, how many miles do you have on your truck? Like some others have suggested, your catalytic converter maybe clogged. They don't last forever. If you do change it out, DON'T go with an after market, high flow cat like Magna Flow as a replacement. If you do, you will NEVER get rid of an error code stating your catalyst hasn't completed it's cycle testing. And, if Ohio is anything like Missouri, you might not pass your emissions test. Ask me how I know. LOL

 

I really don't see why you have to be such a dick, If you didn't notice I actually went and bought ACDelco parts per your suggestion. usually replacing parts with other parts just doesn't make sense. I also thanked you for your suggestion, I don't think I was rude about it at all.

 

I know you said they looked new but did you see them fire ? If they do then you look somewhere else , but at least you know for sure . It stinks, I know but dont skip around . you will find it . I did just as much looking for tests to run , as I did performing them. But when the test checked out ,I was positive it was something else.

 

The plugs are ACDelco, yes I gapped them at .60 and rechecked them at that same gap. I replaced them back when I first got the car and got it running at the beginning of last year. The plugs now still looked good, little bit of black at the top but nothing noticeably bad.

130,000 miles on the car

at idle is really rough, when accelerating the misfire almost seems to go away.
I hooked it to a scan tool and watched the misfire in cylinder 1 happen over 6,000 times in a few short mins while the others all read 0. Also the misfire reading seemed to go up at idle but stop when accelerating.

When I took the engine apart to get to the spider injectors I noticed that it really wasn't clean or dirty in a specific area, the middle seemed to be a little cleaner, I wish I would've taken a pic but I may just take it apart again for some reason idk.

I also used Seafoam last night and sucked it threw the brake booster, which is why it might have looked clean in the middle? It smoked so bad I thought someone was gonna call 911 lol. After doing so I noticed a considerable change. it seemed to run smooth, but after passing 40mph or so it starting blinking again and really this morning just sounded around the same.

It's to the point where I can't afford to just dump money into a cat as a guess. I asked a friend whos a mechanic and he mentioned that while possible it was unlikely that it was the cat cause if it was it would be missing on more than one cylinder. I'm not sure about it but it make sense.

another thing that may be weird is that last year after I got it running but with the misfire, I actually passed the emissions test (smoke test) I was shocked at the time that a misfire would pass an e-check?

As a quick thought does anyone think the computer might be bad?? and how would I know?

again I appreciate everyones help.

 

I did an olms test on all the injectors from the junk yard and all came around 12.5 (should be 11-14)
I had someone tell me I should've swapped cylinder 2 with the junk yard one and moved it over to cylinder 1, this of course after I already did it :/ I may do that soon to see if there's a difference.

You could tell that this car just had work done cause it had a brand new and I mean brand new intake gasket, then where the 2 middle injectors connected there was actual silver showing instead of the carbon residue color over it all, and the 2 pop-it spots were clean too.

 

I have the same issues you are speaking of. I also did a resistance test that checked out ok , but the poppet will not open , I only found that out by checking it .Take the upper plenum off for probably what seems like the hundreth time , reconnect the fuel lines without the plenum, pressurize the lines , and run a positive and ground to each injector pin and see they fire into glass jar. If they all work chances are you wont have to pull that plenum off again. Be careful with fuel and spark you will be exposing both.

 

now that's a test I haven't seen or heard done. I will for sure try that, Thank you, that should be really helpful.