misfires after cam install

**gtptim** · 04-25-2012

Well I just install an XP cam. When I started the car up and leave it idle the RPMs will jump up all of a sudden and back down then it will idle. It do this repeatedly. I have checked for vacuum leaks repeatedly and found nothing. I even took the supercharger back of and siliconed the gasket and it will still do it. I did a compression test and every cylinder is within +/-10 of 160psi. Someone else said I should be using 103s instead of the 104s. The plugs are lapped .060 and I'm using PRJ wires. My current mods is Gen5, 3.4mps, XP cam, TOGs with cat-less down pipe, custom ported head with matching ported LIM, 180* drilled thermostat, and 42.5lb injectors. I'm at a lost to what causing this but I am see some mist coming from my exhaust but I don't know if that's normal for a cat-less exhaust system or not?

**Scottydoggs** · 04-25-2012

you double check the plug wires are on right?

**Rico** · 04-25-2012

A 3.4 with a GEN V? Holy crap Batman!

**sseilmnop** · 04-25-2012

Plug in a code reader and tell us the codes if you have any. Are you getting misfires and if so on what cylinders.

Is the only thing you changed the cam, you already had the gen 5 and other mods on the car and running.

**gtptim** · 04-25-2012

Originally Posted by Rico

A 3.4 with a GEN V? Holy crap Batman!

I should be able to run a 3.2 or push it a little bit and run a 3.0 pulley but the biggest pulley that I had at the time was a 3.4 pulley. I know I got the plug wires on each cylinder rite but on each ignition coil Idk I will have to look when I get back into town. I have an aeroforce gauge but its saying I have 0 misfires but I can go to the back of my car and hear it misfire out the end of my exhaust.

**Scottydoggs** · 04-25-2012

maybe your just hearing the cam?

**sseilmnop** · 04-25-2012

Originally Posted by gtptim

I should be able to run a 3.2 or push it a little bit and run a 3.0 pulley but the biggest pulley that I had at the time was a 3.4 pulley. I know I got the plug wires on each cylinder rite but on each ignition coil Idk I will have to look when I get back into town. I have an aeroforce gauge but its saying I have 0 misfires but I can go to the back of my car and hear it misfire out the end of my exhaust.

I'd stick with the 3.4. Headers and cam don't equal 3.0 in gen 5.

Your getting no codes?

**Fivefingerdeathpunch** · 04-25-2012

.060 plug gap is HUGE

Step it down to .050 atleast

**MoarkatsINmuhtrailer** · 04-25-2012

this^^^^^

**darkhorizon** · 04-25-2012

at idle, too small of a gap will cause misfires... And that being said IDK how mine even runs it misfires at idle so bad.

as far as the idle surging... many things cause that, usually its tuning related and considering you changed like everything... uhh.

**gtptim** · 04-25-2012

Originally Posted by sseilmnop

I'd stick with the 3.4. Headers and cam don't equal 3.0 in gen 5.

Your getting no codes?

How do you figure that? I dont read no mention of ported heads in the quote from you. I do have 2 codes coming up on my aeroforce gauge but there from my EGR valve which I deleted the EGR just didnt delete them from the PCM. Yes the plug wires on everything is correct.

**sseilmnop** · 04-26-2012

Originally Posted by gtptim

How do you figure that? I dont read no mention of ported heads in the quote from you. I do have 2 codes coming up on my aeroforce gauge but there from my EGR valve which I deleted the EGR just didnt delete them from the PCM. Yes the plug wires on everything is correct.

Not sure how to gauge custom ported heads. If you can run 3.0 with no knock great. I think you will end up bigger.

**gtptim** · 04-26-2012

They out flowed ZZP stage3 heads

**Rico** · 04-26-2012

Originally Posted by gtptim

They out flowed ZZP stage3 heads

O_o

How do you know this? Did ZZP put them on their flow bench?

**gtptim** · 04-26-2012

Originally Posted by Rico

O_o

How do you know this? Did ZZP put them on their flow bench?

The guy that did the head work also flow tested a set of ZZP stage3 and then mine.

**Rico** · 04-26-2012

Originally Posted by gtptim

The guy that did the head work also flow tested a set of ZZP stage3 and then mine.

Are they L67 or L32 heads? Is the custom ported intake Gen V or Gen III?

**BillBoost37** · 04-26-2012

Did you remove the P0300, it needs to be taken out.

**Swiggles** · 04-26-2012

Originally Posted by Fivefingerdeathpunch

.060 plug gap is HUGE

Step it down to .050 atleast

103s would be too cold. Gap should be more like .053-.055

a 3.4 on a gen V equals a 3.2 on a gen 3

**afallucco** · 04-26-2012

Originally Posted by Rico

A 3.4 with a GEN V? Holy crap Batman!

3.5 runs pretty good too

Gen V can be fun, clayton is running a 3.4 on his gen V with an s1x cam and derek with his vs. Gonna advance my timing and retune to see what I can pull with the 3.5 and then drop it down to a 3.4 and retune depending on my injectors.