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Misfiring after Gen 5 install!

G

gtptim

New member
Well let me start from the beginning when I first started the car after getting the car back on the road after a year or so of sitting in drive way from being wrecked. I bought a motor and installed it. Like right away it was getting some where around 2-8 misfires so i bought some new plugs and gapped them at .055 but it still did it! So even when I dropped pulley sizes down to a 3.4 on my setup no changes in it! So after a while I then bought some PRJ plug wires and some new plugs again, installed them and re-gapped them agian, no changes yet again! Then changed the ignition coils no changes with that. Then bought a brand new ICM which blew one of my big 40amp starting fuses after i put the old one back and was taking back the new ICM thinking that the new one was bad! So now i installed a my Gen 5 on the car and now some how Im getting 170 misfires with no codes for it at all! I have changed just about every sensor on the car but the cam sensor! Im running out of ideas on whats causing this crap so if any body can help it would help me out alot!
 


Do you know which cylinders are missfiring? Check spark. Injector balance. Or start with a compression check
 
Sat for a year? My bet is bad gas. Honestly...I had to let mine run to blow it all out and I tossed a few bottles of octane booster in and it really smoothed things out.

My question to you...why are you continually throwing mods at it before fixing an issue...especially running a 3.4" on a GenV? I hope for your sake you've got a cam/intercooler/headers to go with that setup. Funny, when you yank your plugs out...are the tips bent at all? If so...then you've got internal damage.
 
You should really change the title.

Misfiiring before 3.4, before new plugs, before Gen V. Please accept my apology in advance, but are you a moron? WTF are you thinking when you have a misfire and think dropping pulley size, or adding other mods are going to magically solve it?

You don't mention new plug wires, ???? If you haven't.. you better
You don't mention fresh fuel ??? if you haven't.. you better
You don't mention if the #4 or #6 wires are touching the O2 sensor wiring.. please ensure they aren't.
You don't mention if the TB was cleaned
You don't mention if you checked for vacuum leaks
You definately don't mention the most important thing.. which cylinder is misfiring.
 
Well, he did say he put on PRJ wires, and it's not throwing a code. However, nothing else about how far he drove it etc.

Lots of aftermarket PCM's have the misfire SES code set to pretty much not show a light, so that could be out the window.

More info is needed for sure. Crappy fuel will not burn well, so have you run a tank of clean fuel through it? Which cylinder is it? If it's one specific one then you can trace down the problem there.
If the P0300 code has been completely disabled, it might not even show up on the individual cylinder, and I've seen this many times.
 


Sorry i did drive it for a while! It does have fresh gas in it since then! I forgot to mention that i did replace all of the vacuum liines! ITS NOT TELLING ME WHICH CYLINDER OR NO CODES ITS JUST SHOWING ME THAT THE CAR IS MISFIRING!!!!! I was running a 3.4 with my Gen3 but Im running a 3.8 with the Gen5! I have been dealing with these misfires and tring to fix them for the past 2 years since i have owned this car and so far not thing else has fixed it!
 
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Because your trap speed is lower than sin. And knock pulls timing in the PCM...and less timing is less power...less power means slow
 


Wanna try different gas station?

Also, please resize your sig or get rid of it.

if you need help with that, just ask.
 
What are you using to scan? If it is showing misses it will show what cylinder. Have you clean the injectors? Fuel filter new? Maf good?
 


matt5112 said:
Wanna try different gas station?

Also, please resize your sig or get rid of it.

if you need help with that, just ask.
Click to expand...

Its not going to matter to me about resizing my sig considering that Im not going to be here for very long any ways since Im getting responses like the ones quoted below! Looks like I found another forum just like clubgp JUST FULL OF DICKS!!!!

bluegtp91 said:
Probably all the time with the pieces of piston missing :p
Click to expand...

BillBoost37 said:
You should really change the title.

Misfiiring before 3.4, before new plugs, before Gen V. Please accept my apology in advance, but are you a moron? WTF are you thinking when you have a misfire and think dropping pulley size, or adding other mods are going to magically solve it?

You don't mention new plug wires, ???? If you haven't.. you better
You don't mention fresh fuel ??? if you haven't.. you better
You don't mention if the #4 or #6 wires are touching the O2 sensor wiring.. please ensure they aren't.
You don't mention if the TB was cleaned
You don't mention if you checked for vacuum leaks
You definately don't mention the most important thing.. which cylinder is misfiring.
Click to expand...
 
1) Try seafoam in your gas. My sister has an 04 Impala. She brought it to me, we switched out stuff from my car to hers, new wires, new plugs, ICM, coils. Nothing fixed it. I could see the misfires on my powertuner, but couldn't figure it out. She took it to a shop that said she had low compression on one cylinder. She put seafoam in it and it went away. Maybe a sticking valve. I don't know. It comes and goes though. It started doing it again a couple of months ago. Same remedy. I have no explination

2) Blue is a dick.
 
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