Imo000

Try disconnecting the MAF and see if it helps with the idle. Maybe the TPS or the idle switch isn't working.

zekgb

After my initial impression of improvement the idle really was pretty poor with a noticeable miss. Took it to local shop to have a smoke test done, no leaks found with smoke or with a propane enhancer so looks like I did that part of the job ok. We then hooked up a smog machine tailpipe sniffer and HC was off the charts at idle (gross polluter territory) but much better (would pass) when run at 2500 rpm. NOX was very low in both tests I guess this indicates a very rich condition? Once home I started pulling plug wires while at idle and there was no change when pulling the wire on #8, all other cylinders changed idle noticeably when wires were pulled.

Will check to make sure the injector is firing and that I have spark before jumping to compression and leakdown tests. I'll also pop the TB covers and verify timing. Anything else I should look at?

zekgb

Ugh. Compression test results (warm engine, dry cylinders):

145
155
150
150
140
150
145
35

Houston, we have a problem. I re-ran 8 wet and didn't see any difference.

We'll do a leakdown over the weekend and I may buy myself a scope as an early Xmas present to see if there's anything obvious going on in there. Sigh.

Imo000

If re running the test wet didn't make an difference and the engine isn't backfiring into the intake then the problem s a burnt or bent exhaust valves. And this can't be seen with a scope. Just pump some air into that cylinder, the noise should be coming out at the exhaust.