Thread: unique idle issue

Hey everyone,

im new to the forum but have been reading threads here for quite a while now.

my mod's on my car are as follows:

02 gp gt
zzp ssm90 kit (ported)
zzp 3.8" mps pulley
zzp tb spacer
zzp hv tb stage 1
k&n cai
zzp 10.4mm plug wires
autolite 104's
zzp fuel pump rewire
zzp alt voltage booster
gtp rad
zzp 180* tstat
zzp gtp injectors
zzp pcm
zzp fuel logs with fuellabs fpr
zzp 2.5" catted downpipe

also i have the zzp ss intercooler that i have not installed as of yet


on to my actual issue.

since installing majority of the above items i have had this unique issue that im not sure where to look.

if i leave the car overnight without starting it, when i go to start it the first time it wont start unless i prime it a few times. once the car is running and idling at cold it will randomly start to hunt up and down. if i decided to drive it while it is doing this it will buck and feel like its misfiring. once the vehicle is warmed up it will not do this ever until i leave it overnight again.

i scanned for codes none shown but i do have misfires reported in the misfire history


any ideas would be great

thanks

Mike

Originally Posted by 02bluegtss

Hey everyone,

im new to the forum but have been reading threads here for quite a while now.

my mod's on my car are as follows:

02 gp gt
zzp ssm90 kit (ported)
zzp 3.8" mps pulley
zzp tb spacer
zzp hv tb stage 1
k&n cai
zzp 10.4mm plug wires
autolite 104's
zzp fuel pump rewire
zzp alt voltage booster
gtp rad
zzp 180* tstat
zzp gtp injectors
zzp pcm
zzp fuel logs with fuellabs fpr
zzp 2.5" catted downpipe

also i have the zzp ss intercooler that i have not installed as of yet


on to my actual issue.

since installing majority of the above items i have had this unique issue that im not sure where to look.

if i leave the car overnight without starting it, when i go to start it the first time it wont start unless i prime it a few times. once the car is running and idling at cold it will randomly start to hunt up and down. if i decided to drive it while it is doing this it will buck and feel like its misfiring. once the vehicle is warmed up it will not do this ever until i leave it overnight again.

i scanned for codes none shown but i do have misfires reported in the misfire history


any ideas would be great

thanks

Mike

I have a 2001 Grand Prix GT with the SS M90 kit as well. I have a rough idle and the RPM is all over the place when it's cold. I would love to hear the answer to this question as well!

P.S. How are you running a 3.8" pulley without more flow mods? I get knock retard with a 4.0" pulley and I have a CAI, headers and full 2.5" exhaust.

I think he was saying he had a 2.5" catback...

my next upgrade is going to be the ssac headers or speed daddy with no question and cat back is stock exhaust

I cant remember for sure but i think the p0300 was listed in the codes but my ses light is never on.

Originally Posted by 01gpgt01

Id like to see a scan of your setup. You're tune must blow

It's a canned tune and I can't find anyone who is willing to tune it, so I'm out of luck I guess.

Time to get HPTuners and a wideband.

Or try a bottle of some quality octane booster and see if the knock goes down, if it does, the knock is real, if it doesnt, then its false.

Originally Posted by matt5112

Time to get HPTuners and a wideband.

Or try a bottle of some quality octane booster and see if the knock goes down, if it does, the knock is real, if it doesnt, then its false.

I'm selling my wideband for the sole purpose that I will never have the time to learn how to tune. I run 94 octane fuel, so there is still a possibility the knock is false. Could the transmission dipstick rubbing up against the headers cause false knock?

It could, I wouldnt want them touching for heat reasons though.

94 Octane is E10 last i heard.

That tends to have a slightly different stoich and rich/lean AFR's. Might affect your tune.

Originally Posted by matt5112

It could, I wouldnt want them touching for heat reasons though.

94 Octane is E10 last i heard.

That tends to have a slightly different stoich and rich/lean AFR's. Might affect your tune.

Okay. I'll try putting header wrap around the spot that they touch. 94 Octane (from Husky) is 91 octane with 10% ethanol added.