Brandon Cole Hurdle

This is driving me insane. So I ported my intake and throttle body last month. I put it all back together and besides a higher than normal idle (1200rpm) it ran great. I drove it a few days out of the week with no problems at all. Randomly this past Wednesday it decied to start surging/sputtering at partial throttle. My AFR runs up lean when I give it alittle gas and the car starts jerking and surging. The next day I was scheduled for a tune and it drove like **** all the way there on the highway. WOT dyno pulls were as smooth as they could be and tuner said fuel tabes looked fine. I even picked up 22whp from my ported intake! But as soon as I started the drive home I had the same problem. Most wot pulls are perfectly fine but trying to drive like a normal person is annoying and almost impossible? I've checked for vaccume leaks with started fluid and propane and found nothing. I changed plugs and that seems to help maybe alittle but still not right. Now I have no clue? Any ideas

irok

lots have damaged a tb when porting

Brandon Cole Hurdle

My first thought was that I messed up the throttle body but it's weird it ran perfectly fine with the ported tb for a week or 2 then randomly started acting up

devnull

When I read the title of this I immediately thought "ported TB".

Read post 15 (start there) --> https://www.corvetteforum.com/forums...post1592298998

Hope that helps explain a little. I put one in my C7 and removed it after similar experiences. Many of these work fantastic, but I didn't want to deal with it...

Dcasole

The higher than normal idle and lean ...u sure u don't have a vacuum leak ??

I ran into same random issue when I installed my 102 manifold, ended up being one of the plastic lines leaking just behind the throttle body ....

Dave

Brandon Cole Hurdle

I've checked for leaks didn't find any. My first thought was that since I cut out the ridges in the tb it's getting more air through causing the high idle. Which is annoying but I don't think it's related to the surging because it was fine driving for weeks like that then randomly started the surge

Brandon Cole Hurdle

It's weird that it was fine for weeks driving then started but that's exactly how mine is. 20% throttle it's bad cause I got rid of that whole ridge and noticed the space difference. That's a really good point.... damn I'll try switching to a stock one thanks!

Dcasole

Let us know how it works out ,look for signs of a leak when u take the manifold off


Dave

Brandon Cole Hurdle

So this is interesting. I washed it this morning and hooked up my scan tool to go for a short drive and see if it reads a misfire or something weird in the throttle position but it ran flawless. No problems at all.....

Dcasole

I am telling you , look at that plastic vacuum line to the left of the engine just behind the throttle body , my LS3 plastic coil cover was rubbing on mine as it does not line up as well as it did when I had my stock LS3 manifold , this caused a slight misalignment in the tube to the joint which was leaking intermittent. drove me nuts until I wiggled it and my IDLE instantly returned to the correct RPM's . These hoses are not like the old rubber hoses , they have to be perfectly aligned to the nipple or the grey locking ring will not latch. Also check the one on the other side
Also check the MAP and MAF sensors . If you took the MAF out there is an arrow engraved on it to show the correct airflow direction .

It ran before you took it off and I am having a hard time believing that PORTING would cause it to surge " SOMETIMES" . if it was the porting it would do it all the time

Dcasole

This would not make the car idle faster ......

Dave

Brandon Cole Hurdle

what i meant by that is i got to low under the blade which would cause i higher idle. and ever since sunday I've had no problems the partial throttle surge is gone. runs like a bat outa hell. i have no idea what caused it but i have no doubts it will come back again.