Misfire, code 0303, plugs wires changed. Injector?

[kennedyrec]

Got a code for a misfire (0303), and after installing Belden wires and NGK Copper plugs (original at 150k), still have it. Car does have a pretty good miss when running. I put a 194 bulb in the injector harness for #3 cyl and its firing, but the telltale "tap" from this injector is very faint, of at all. Can the injector be cleaned, or is it strictly remove/replace? Thanks-

[00Beast]

You could try any of the gamut of injection system cleaners, Gumout Regane, Amsoil PI, Seafoam, etc. The best way to check is to take a long screw driver or mechanic's stethoscope and hold it against the injector (which is the front middle) and hold it to your ear and hear if it's clicking firmly, compare it to one of the others. You could try gently tapping it with the handle of said screwdriver to potentially loosen something up.

[kennedyrec]

I'm a little hesitant to try my go to fuel cleaner (Seafoam, marine use primarily) because i have put in excess of 400,000 miles on numerous Bonnevilles. These miles include some cars that were approaching 250k on the odometer, and this is the first Injector issue. The screwdriver technique is the diagnostic testing method i used. Can the injector (if removed) be cleaned?

[00Beast]

It can, but it's probably going to be a better bet to replace it.

[kennedyrec]

Any suggestions on a replacement? New, used, ebay? Many thanks- Krec

[01bonneSC]

Andrew (harofreak00)

[00Beast]

That is if the L67 and L36's have the same injectors...

[kennedyrec]

Per Andrew, they are not~

[01bonneSC]

Oh yeah, forgot his engine parts are all L67. I got my injector from him when I had my SSEi.

[Ken_W]

I'd go with used, from a yard, or eBay, or whatever. Shouldn't be hard to find for a GM3800. Get two, just in case one's a dud; they should only be around $10-$15 each used. New ones are around $75-85.

I replaced one in my SSEi last summer and this did the trick.

I would suggest, however, running some injector cleaner through first -- for $10, roll the dice and you might get out of this without having to do anything else. The cleaner took care of my son's '99 Grand Am GT that was throwing codes last October. I put in a bottle of Techron and the problem completely went away in a couple days and has not returned.

Ken_W

[robauto]

did you resolve? I just went thru code 0301 (#1 cylinder) on a 3.4 chev equionox with aluminum heads. I had a bad plug and it fixed it for now. the plugs had 95k, all others looked ok. I am still tryin to figure out why the plug failed, but for now the car is running great.
I did alot of research, talking to buddies and came up with alot of ideas. you tube has a great video from an autolite technician, search for code p0301 in you tube.
how did your #3 plug look? these cars use iridium plugs, you should replace with them, use ac
I agree try the chevron techron fuel injector cleaner, no sense in removing the injector, you cannot clean it
the stethoscope listening is a good check, you can tap with a hammer and extension as it running, go lightly, to loosen any debris
the injector replacement is simple, if you did not already, you can replace
a few simple things to try- look for vacuum leak, spray around #3 cylinder and listen, you can also watch your stft (fuel) on the scan tool
could be a weak coil, switch coils with another bank and see if the code follows it, or just replace the coil as a try
watch the autolite video
let me know if you came up with anything