Ok here is the story. Car ran fine last friday night and was giving me 0 issues. Fast forward to Saturday I take my roommate to the airport. Car runs fine and after I drop him off at the airport it starts to sputter at wot.
I drive the car to our shop and redo my cooling system and intake. Fast forward to today I start working away on the sputtering. I buy a new coil and start swapping them out. After i swapped out the first coil I fill up with gas. I try to start the car and the only way to get it to start was if I cranked it and held the gas to the floor. Car ran a lot worse. So instead of sputtering under load it would do it while sitting also. Car will idle fine though.
So I finish swapping all the coils. Nothing. Checked the fuel pressure and it sat at 64 psi and would drop to 60 with the car shut off. thought it could be the injectors so I listened to them with a stethoscope and they all sounded the same. Put some heat in the gas and it helped a little bit but it Still runs like crap and if I need to start it I have to hold down on the gas and crank it for 3 seconds. Car idles fine just runs like crap. Also pulled one of the plugs off and it is very black but dry. Any ideas?

I had a buddy of mine look at it and he thinks it is running lean. Possibly o2 sensors?
Also behind the intake I found 2 hard vacuum lines that were not plugged in. One has a 90 degree bend and one is straight. The 90 degree bend one has suction. I looked all over the motor and cant seem to figure out where it goes.
im only running the 2 pre cats.
This is a LS1 swapped E36 BMW and here are the specs.
1998 camaro motor.
Ram Stage 3 clutch.Patriot Stage Two Head & Cam pkg.LS6 style heads with 59cc combustion chambers, 225cc intake/83cc exhaust runners and 2.02" intake/1.57" exhaust valves.cam has a 228°/224° duration at .050", .591"/.583" lift, 112° lobe separation.


for the love of god someone help!

 

First off you need to refrain yourself from flooring your car when trying to start it, its not good and just plain stupid. If you have serious mechanical damage you can make your matters even worse. Never ever floor your car when starting from a cold start, its very bad on your valve train. Second, it could be many things that are causing your problems. But the first thing that comes to mind is your o2 sensors. Have you had any service engine soon lights? Have you tried cleaning your maf sensor? When were the plugs and wires last changed? Are you getting any mechanical internal engine noises at idle?

 

The car was already warm when I did that but thats besides the point.
Anywho there are no service engine lights currently hooked up since the motor was swapped into a completely different car which was a OBD1 chassis so scanning the car for any faults is completely out of the question. I havent tried cleaning the MAF yet but will give this a shot. I just changed the plugs and wires probably about 600 miles ago give or take. NGK plugs with MSD wires.

 

Well I believe I figured out the problem. I cleaned my maf as it was covered in black crap. Put it back together and the car started right up. Let it warm up and took it for a drive and the car ran fine. I shut the car off and started it back up. BAM back to crap. Cleaned the o2s and no change. inplugged the maf and took it for a drive and ran better. Shut the car and ran to get some brake cleaner and visited s buddy. Hour and a half 2 hours later with the maf plugged in it started right up. Turned it off tried starting again and it took a bit longer.

 

Greeky the car does have a lot of mechanical noises at idle. Sounds mostly like the injectors though and nothing that wasn't there before

 

Air leak somewhere... Clean your throttle plate off good and the IAC ports? How recent is the swap? Has it been tuned? Is there EGR on this? That could be the smoking gun right there. When that gets stuck open the car will run like ***.

Something is letting air in and it's being compensated by more fuel. What intake manifold? (Stupid question) LS1? LS6 or FAST?

 

I did clean off the throttle plate. Took the whole thing off. The swap is about a couple months old. There is no egr and I it was tuned. After I put it all back together I did the brake cleaner test and the idle didn't change. The car still has the ls1 intake.

 

I went ahead and sprayed some brake cleaner underneath the intake manifold and still nothing. Now I only get the hard starts and the stuttering/missing after the car is warm.
Im still leaning toward a dead or dieing maf since it runs better warm with the maf unplugged than plugged in.

 

video of the car running. Was running normal at the time because it wasnt 100 percent hot.

http://www.youtube.com/watch?v=TzX3ZjINgZU

 

Well I found the problem. It was a combination of a dieing maf and a small leak in my passenger side header. I noticed it smoking before and checked and found some old wire protector tubing melted to it. Since the header is wrapped I didn't see any noticeable exhaust leakage and didn't hear it till a foot away from the collector. I pulled the wrap back a little bit and saw black soot. Not quite as obvious of a solution but glad I found the problem. Also replacing the maf did fix my crappy start issue

 

the plug you referred to in the back with the plugs is for your EVAP set-up. no plug in no air from main vents . . . or at least thats how it is with my car

 

You need to go to the junkyard, and find ANY 1996 or newer GM vehicle, go under it's dash, and take the OBD2 port from it, with a few inches of the wiring.

Next step, is to connect all 3 of the necessary wires for that port to work (ignition power, ground, and the data wire to the computer). It will only take a few minutes, and will make troubleshooting the car a bazillion times easier without randomly throwing parts (like ignition coils) at it, and randomly taking other stuff apart.