You can replace the straight rubber vacuum connectors with 7/32" and 9/32" vacuum hose (about $2 total for 1 ft. of each). The "Tee" coming off the throttle body has to come from your local GM dealer. I think I paid $2.80. gmpartsdirect.com wanted me to by a pkg. of 5 for about $0.90 less/ea. I probably should have done that in retrospect and then could have offerred the extras to others here. Ah well, hindsight....

Don't be real worried if your on the lower side of that spectrum since you do have a bigger cam. But if your way off then more than likely you do have a vacuum leak.
Are you still going to get a different scanner?

Alright...... got some info for you all.


First of all, my body decided to manufacture some testosterone, so I had the guts to fire the car up and take it out for a brisk run. Upon finishing that run, I'm convinced the car'* internals are perfectly fine and it'* running as smooth as ever. I'm also convinced that this scantool is no good at capturing data, and that I need to get an LS1M. Ideally a Powertuner would be nice, but I have neither a laptop nor the money to spend on the software. I just need the best bang for the buck that I can handle at this point. If anybody can locate a cheap Powertuner package for me I'll definitely consider it, but as of right now I just need a good, reliable scanner.

So, without further ado, here'* the MAP sensor data I collected. Keep in mind, this is from my AutoXray, and may or may not be correct.

Cold idle - 13-14 in.Hg
Hot idle - 13-14 in.Hg
2k RPM - 9 in.Hg
3k RPM - 8-9 in.Hg

WOT (in gear, under load) - 29-30 in.Hg


Not sure if my vacuum is where it'* supposed to be under load, but that'* what the scantool is telling me. Also, during the short times I was watching I saw no KR, and the scanner didn't register any during my data capture run. However, I'm not sure about reliability because I have a scan log that shows TPS at 100%, RPM at 4297, and only -20.5 degrees of timing advance. I just don't know if those numbers make sense.

Heck, I wasn't going to enter these numbers into Excel, but I might as well. Here'* the scan data. You tell me if the numbers look wonky or not.




Additionally, I ran to the parts store and grabbed some carb cleaner. Sprayed little bursts on all the vacuum connectors that might be problematic, but there were no stutters in the RPM. I guess that eliminates some options, eh?

Ok. I'm convinced you should get the LS1M too. You should not be getting your highest vac reading at WOT. Man that thing is strange.

Well, I had a bad misfire tonight that didn't go away. I didn't put the scanner on it, and I'm hoping its just a fouled plug. Will check tomorrow and let you guys know. Still don't have the AFC either . It should have been here by now, so we'll see if the guy makes good on his deal.

Cross your fingers and hope it'* just a bad plug!

When I was running waaaay lean in the midrange, I had a couple misfires. I bumped up the afc and it want away.

You sissy! Get out there and pull a plug or two!

Well, still no AFC. Should have been here today, and I'm getting really antsy.


Other than that, I checked my misfire code and it turned out to be cylinder #3. Pulled the plug, and it was all black. All I had was a wire brush, so I scrubbed on it a little and put it back in. Car kept misfiring for a couple minutes after that, then cleared up while I was idling in a parking lot. At least that means all the internal parts are okay!

Hopefully I'll receive the AFC tomorrow, and install and tune on Sunday with a better scantool. After that comes a custom PCM, and then a dyno pull to top it all off

All black? Thats not good. You should get new sparkplugs when you get the afc and start tuning.
Could you take a pic of the plug? I hope it'* not all oil fouled like mine was.

Wife has the digicam right now, so I can't take a pic. I don't think it was oil-fouled. Head gaskets are new, heads were magnafluxed before milling.... it shouldn't be leaking oil anywhere. It was just a sooty black that came off easily with the wire brush. I'll try to get pics tomorrow.