Cooldude5231

iTrader: (6)

a little background:
when i bought the car, the owner didnt take care of it.
ive since done a COMPLETE tune up just 6k miles ago
last week i ported the throttle body, and upgraded to the ls6 intake.
so no more egr, air system, etc
the car idles high
right around 1100 rpms.
when i tune it for the ls6 intake, egr, and air system delete im goin to idle it down. (the IAC is working correctly)
anyway on to my problem.
if i sit and hold the throttle in between 1300 and 1500 rpms it feels like its missing terribly.
like the whole car starts shacking and the motor looks like its going to rattle out.
the only codes its throwing are for the egr and air systems
the car runs great and pulls pretty hard for a relatively stock z28
i run premium gas, i just seafoamed it about 700 miles ago, ive been putting lucas injector cleaner in the fuel, cleaned the maf, etc
i just dont understand why its struggling.
any ideas??
thanks guys!

Cooldude5231

iTrader: (6)

84 views and no one has any idea???

Old Geezer

iTrader: (3)

Here's one: Data log it, and see what shows up. You should be able to see misfires, and other ?? readings, that may be causing the issue.
Update the tune with the deleted items, then log it....

quik95lt1

iTrader: (7)

probably a lean misfire issue does it do it cold and warm or jsut warm? get a data log for us its most likely a tune issue when you say you "deleted" the evap what did you do? plug the intake port or just dissconnect it?

jrob56

iTrader: (39)

The car should not idle that high, you sure you dont have a massive vacuum leak somewhere? or your throttle blade isnt hung open or something?

Cooldude5231

iTrader: (6)

excuse my ignorance guys, but how do i data log??

im sure i dont have a leak.
i just re plumbed all the vaccum when i put the ls6 intake on because the original lines were melted in half
i replaced ALL the intake gaskets and the throttle body gasket, so theres no leak anywhere

bronx_peanut

O2 sensor could be going bad. Bad plug wires or maybe not pushed on all the way.

jrob56

iTrader: (39)

you are gonna need some kind of tuning or logging software that Im guessing you dont have. Id try to find someone local that can take a look for you. Thats what I did not to long ago to check my A/F and see how the car was running before I had it tuned.

To me the high idle sounds like you are getting in more air somewhere, you check that TB is closed all the way. You replace the coolant lines with ls6 style or trim ribs underneath? I ask because if not, intake might not be seated down all the way.

I also noticed you did your porting yourself? Any pics of it? Did you grind the throttle stop at all? Reset TPS?

joecar

How did you re-plumb the vacuum...?

How did you check for leaks...?

[ just sanity checking ]

Cooldude5231

iTrader: (6)

I have motec but no way to book my laptop up to my car. I posted a thread on the tubing section asking if the said obd2 cord would work but no answers.
I just shaved the bottom of the intake, but I know its seated all the way.
Checked several time before I installed.
I can take pics in the morning when the sun comes up.
No I haven't grinded the stop yet, and no I didn't reset the tps
The car has idled this high since I bought it a few months ago.
I used fuel line and t's to redo the vaccum hoses, along with a new pcv valve.
I checked for vaccum loss around the connections via starter fluid but was sealed tight.

LilJayV10

iTrader: (39)

How do you know how to tune but don't know how to data log?

So it did this before the intake swap also?

Cooldude5231

iTrader: (6)

I didnt know motec was a tuning program too.
I've never used it.
I just downloaded it earlier this week and have not gotten a obd2 usb cable because i wasn't sure if I had to have a special one.

Cooldude5231

iTrader: (6)

Yes it did idle high before I swapped intakes.
As for missing, Idk.
Never tried.
I found out it was doing it on accident.
One foot on clutch other on gas pedal at a stop light and didnt realize I was pressing the gas till i felt the whole car start shaking.