So the Monte was leaking oil and I decided to replace the upper intake manifold gasket. All went well until it was time to start it up... It starts fine then dies within probably 1 second. If throttle is applied it runs very very rough like its dropping maybe two cylinders. I have checked the plug wires, all sensors are plugged in, all injectors are plugged in, fuel system is pressurized. Think I got dirt in an injector? I'm kinda of lost on what to do. Thanks all! BTW it's an 03 SS 3.8L nat. aspirated

 

how is the fuel pressure?

check your Maf and Iac

 

- Is the firing order correct? Are the plug wires going from the correct coil to cylinder? If not, that explains the rough performance while giving some throttle.
- Check for any vacuum leaks?
- Any other leaks?

 

Fuel pressure is good. Checked firing order 3 times, wires are correct(this originally was what I thought the issue was). How does one check the maf and iac? Like the resistance test on the plug? Will check vacuum system tomorrow and stuff and post back, been on it since 9am this morn, thx for the help!

 

Unplug the MAF to check it

Make sure you didn't plug the MAP connector in backwards

Did you put RTV on the edges of the gaskets?

 

I did not, guy at auto parts said it didn't come with any so I didn't need it, the old one didn't have any either. This is the upper manifold gasket we are talking about not the lowers. If this doesn't fix the leak the lowers are next.

 

Sounds like a vacuum leak to me. Had similar symptoms when I reinstalled my plenum once and messed up one of the gaskets. Would start and instantly stall but could keep it running with the throttle but it ran terrible. It runs rough because it is running incredibly lean and missfiring.

 

For what it's worth, IMO if the LIM is not the aluminum gaskets, you should have gone all the way down and been done with it (since the nylon has a known rep for failing).
Regardless, everything that needs worked out will get there.

Since this problem of dieing shortly after you start it and rough performance while rev-ing did not exist prior to what you did, retracing your steps may be in order.

Also, I just thought of this one... Did you use new injector O-Rings or re-use the ones that you exposed (on the bottom of the injectors when pulling the fuel rail out)? If you did NOT replace them, I would advise that you do. Old O-Rings sometimes don't seat back in properly, don't make a seal and will cause a host of problems. Could be one problem area. That and did all the injectors seat?

I found when parting out a friend's car he did not seat an injector right one time and that was part of the problems he had with the car.

Also, don't forget to check for vacuum leaks.

 

I re-used the old o-rings, read online that replacements were of poor quality and the originals looked fine. I briefly went over the injectors, all are tight and seem to have seated well. I will post back here tomorrow after working on it in the evening. Thanks for all the tips!

 

Video of it turing over with no throttle. That's it for the night!
Monte - YouTube