Engine stuttering really bad before running temp?

[05GTI6677]

86 Cabby with the 1.8, when I start my car and the engine in cold (not the weather) it will stutter really bad for about 5 minutes until it warms up a little, it has brand new spark plugs that are gapped correctly, wires are in good shape, new distributor rotor, new fuel pump/filter. If you give it a lot of gas it will push through it and run regular but during normal driving before the engine is warmed up it sputters a lot. That's the best explanation I have, any ideas or suggestions would be appreciated!

Thanks

[ziddey]

running lean before o2 sensor comes online.

fix those vacuum leaks

[Fat Rabbit]

That missing hose is a big vacuum leak. First thing is to plug it and see if that fixes the issue Also check the rest of the vacuum hoses for leaks. I'd probably also check the Idle Air Valve to see if it is operating properly. A nice vacuum system diagram was posted in your other post. You can use that for reference. The idle air valve works off of 12V DC and engine heat to initally supply additional air for engine warm up then close off after a period of time when the engine is warm. People tend to mess with the idle air bypass adjustment screw in the throttle body instead of actually fixing any unmeasured air issues (Vacuum leaks). So once all of the vacuum leaks are found and the idle air valve is assured to be in working condition you might have to adjust that throttle body screw. Incidentally, that screw has an "O" ring which can itself be a leak source. Sometimesthe screws vibrate out of the throttle body or mess up on their own. Do the simple -- obvious things first. FR