$500 in parts- now have stumbling issue

[scabzzzz]

I dont know man. I think you're just overlooking something.

When you figure it out, you'll probably kick yourself.

[bimmerboy12]

bmwpower, what plugs did you end up using that solved the problem???
One thing that I will add: Sometimes I start it up when it is cold (and 25 degrees out) and the idle will waver about 200 rpm in rhythmic fashion, about one cycle per second. Then when warmed up, it will just stumble in random around -100 rpm, so little that it hardly registers on the tach.
I am doubting a vacuum leak at this point as I have scoured the engine with a tubed stethoscope, ether, etc. and have turned up nothing. When I pull the dipstick it immediately starts idling WAY WORSE. It seems electrical to me.

[twright]

I think you have a vacuum leak. And don't forget that an oil leak on this engine (valve cover, dip stick, etc.) is also a vacuum leak.

[scabzzzz]

Ive heard of weird issues with the two prong plugs as well, but I just dont see it being that.
Does it just seem like it has a lobey idle? Like you've got a hot cam in it or something?

[bmwpower]

The timing belt was put on right, I rotated and verified the markings were lining up correctly per the Bentley manual. It is pretty obvious if it is a tooth off. I swapped the old CTS back in for the old with no change. I bench tested the old and the new CTS per the Bentley manual and they checked out fine. The wires are correct as they are numbered (from Bavauto). The plugs I am using are Bosch Platinums (not +2 or +4). Is this OK or should I have used standard Bosch plugs?
I did not check the clearance on the TPS, I don't know why it would have changed as I did not touch it throughout the procedure. Bentley manual doesn't say much about the TPS when I look it up.
I will try unhooking the battery for more than 30 minutes. Hell, I will try anything at this point.

My money is on the plugs. Like I said, I had problems before using the plugs you're using.

[bimmerboy12]

Have you tried to unplug the battery for 30 minutes and plug it back up? Doesnt the Motronic on your car adjust fuel rates on its own?

Did you put the CTS in the wrong spot? Mix the wires?
Have you checked the clearance on the throttle position sensor?

The timing belt was put on right, I rotated and verified the markings were lining up correctly per the Bentley manual. It is pretty obvious if it is a tooth off. I swapped the old CTS back in for the old with no change. I bench tested the old and the new CTS per the Bentley manual and they checked out fine. The wires are correct as they are numbered (from Bavauto). The plugs I am using are Bosch Platinums (not +2 or +4). Is this OK or should I have used standard Bosch plugs?
I did not check the clearance on the TPS, I don't know why it would have changed as I did not touch it throughout the procedure. Bentley manual doesn't say much about the TPS when I look it up.
I will try unhooking the battery for more than 30 minutes. Hell, I will try anything at this point.

[Funkmasta]

So you're positive that you put the t-belt on correctly?

Another vote for timing belt being a tooth off.

[bmwpower]

Which type/brand plugs did you use? Anything but the factory stuff makes my cars idle like shit.

[scabzzzz]

Have you tried to unplug the battery for 30 minutes and plug it back up? Doesnt the Motronic on your car adjust fuel rates on its own?

Did you put the CTS in the wrong spot? Mix the wires?
Have you checked the clearance on the throttle position sensor?

[evil_twin]

So you're positive that you put the t-belt on correctly?

[bimmerboy12]

Update- removed cap and inspected cap/rotor, everything looked fine. Verified all wires were plugged in all the way. Checked booster vacuum line, no leaks.
Problem is still there.

[bimmerboy12]

Update time... removed the ground strap and wire brushed all contact points. Checked for vacuum leaks at filler cap and dipstick. Bought new MSD Blaster coil and installed. Removed O2 sensor and bench tested OK.
The problem is unchanged.
Next I will be taking apart the cap/rotor/wires and search for anything... Im getting desperate.

[OrganicMechanic]

ground strap?

[SpecM]

Here is a wild thought: I tested the coil and I am getting zero resistance when I should be getting resistance according to my Bentley manual. Therefore, it is not right. Since I replaced the wires, cap and rotor (which were all in pretty bad shape) would the car be more sensitive to the coil being bad/not good? What are the symptoms of a bad coil anyways?
Thanks for all your help guys.
Brian

the coil resistance should NOT be zero... should be a few thousand ohms, I think

see if you can swap it out with another one, or my a cheap one at Advance Auto (new MSD blaster coil only $35)

[xLibelle]

brake booster leak? you'd hear a hiss. pull that line and plug it. remember your brakes will be minimal if you go for a drive.