Rough idle and sputtering exhaust noise
 

Just completed my engine rebuild for my early NA. Things went pretty smoothly, except for a few of my own screw ups. Trying to finish it out and am having trouble with a rough idle. It almost seems like it is running on 3 cylinders. I checked all the injectors and the spark plugs and everything looks fine. Compression looks consistent across all 4 cylinders. I have replaced the vacuum lines with no change.

The engine actually sounds really good from the front. The exhaust is what sputters. The car shakes a bit at idle. I was also thinking the balance belt might not be on properly after I removed the pullies. I might try to remove the balance belt for a trial.

The catalytic converter appears to be clogged. There is air be pushed out of a hole on the side of the cat. You can see the hole at the end of the second video.

Check out the two videos. Any suggestions would be appreciated.

http://www.youtube.com/watch?v=PhaSP9XMlws

http://www.youtube.com/watch?v=EPQ6goJO0aQ

Thanks

Wow! The idle stabilizer does a whole bunch of work. That was the problem. I cleaned it out with PB Blaster and it was working great. Back to a good idle.

Now for a few suspension upgrades.

Lets see some new video now after it is running better.

Hey did the sound speed up when giving it throttle? I think I may have the same problem...
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Glad you fixed your problem but I'm not sure what cleaning out the idle stabilizer with PB Blaster actually means. Were the balance shafts out of alignment?