Just swapped a 99 intake on my jeep last week, along with the 703 injectors I already had in before. On cold starts it either runs really bad, or stalls and wont start unless you hold it wide open and then continue to hold the rpms up for a bit for it to run on its own.

But when its up to operating temp it runs great!

Any ideas??? I'm almost ready to put my old intake back on.

 

vacuum leak, use carb cleaner and spray around gasket area and listen for idle change.

 

Check for vacuum leaks.

 

I'll give that a shot. I'm also getting a check engine light on cold starts

 

I'm a little bit late updating this, but I did find the issue!

When I originally swapped intakes I had forgot to buy extra line for the vacuum lines as the ports are in different spots on the intake, and some lines have to be extended..

Well because I didn't have extra line originally, I ended up joining the rear PCV line and MAP sensor line into a "T" then into the manifold. I figured that may be the issue so I bought some line and run the MAP and PCV to seperate ports and it fixed it right up! Runs like a charm

So my best guess is that the engine had so much blow-by on cold starts that the MAP sensor was not reading correctly and causing my issues.

 

? doesn't your MAP sensor mount on the throttle body and sources it's vacuum from the throttle body?

 

map is on the firewall

 

It's on the throttle body on 96 and newer.

 

Thanks.