viciousknid

iTrader: (8)

sounds more like fuel delivery to me. but i'm still a rookie.

terravast4

iTrader: (25)

Well, replaced all spark plugs and all wires and I am still pulling misfire for #1 cylinder so I replaced the coil...............still misfire. I guess it must be a bad injector. Anyone out there that can tell me how to test it I would appreciate it. Do I just ohm it out or something??

budhayes3

iTrader: (19)

You could ohm out the injector, but that will only tell you if the coil is open, shorted, or has excessive resistance, it won't tell you if the injector is clogged or if the pintle is broken. If you suspect the injector, you could swap it with another and see if the misfire moves to that cylinder. Do you feel an actual misfire, or is there a possible tuning issue?

Did you figure out the cat converter codes yet?

terravast4

iTrader: (25)

I don't feel the misfire. If I didn't have the blinking light I wouldn't know anything was wrong and I am beginning to think the cat code is being thrown due to the misfire and incomplete burning of the fuel. I was thinking of switching to some 60#'s so now may be the time. Funny though just crusing around everything is just fine, part throttle downshift still good at wot downshift light starts blinking but cannot feel a performance difference but I always shut it down right away. Like I said earlier this came right after the install of longtubes and the y-pipe....maybe the extra air flow is just enough for the tune to need a tweek. maybe I was close to maxing out the injectors and this just put me over the edge.

budhayes3

iTrader: (19)

I suppose tuning could be the issue....if I didn't know that the cats were new, I'd say that they were the problem. When tdrumm's grand prix had bad cats, he didn't get cat codes but got misfire codes with the blinking light. It also had no power above 4k though

I guess that the next step would be to get some logging software hooked up and see what the data says...

Allgonoshow

iTrader: (1)

my truck had 420/430 codes after dynatech header/cats installed. that code means
cats are flowing too much exhaust for the cat to process, need tuner to disable rear o2's to fix.
can't say what the misfire stuff is, could need a re-tune for headers if everything else
double checked and ok

terravast4

iTrader: (25)

Thanks, i thought the opposite. I thought the code meant the cat's were not flowing enough air.