You're right about street racing...it was my second and last time doing this...just prolly a heat of the moment stuff...I have tried the blazer at a strip a couple of times and do not approve on street racing also...Last time when it was stock I ran 16.8s...will go someday to the strip to try with the mods I have done to see how much I pullin the 1/4...
I have put mods only 'cause I love the sound it has now and the added torque...


Regarding what I said about bad idle when hot, do you know what this could be?

 

I'll have to think on that for awhile and re-read this entire thread! I'm very busy with work at the moment, but should be able to get back to it later tonight.

 

My '00 is also gapped at .60.

 

As soon as I get out of the office I will check each one of the drivetrain mounts, just in case I misplaced one or something...just a thought...haven't pulled the rabbit outta the hat yet!

 

Guess what? Pulled the darn rabbit...!!!!!!!!!!!!!!!

Abnormal shaking @ idle is gone!!!!!!!!!!!!!!

I checked the passenger side and drivers side engine mounts and looked ok...did not trust my instincts and decided to take them out...I took all nuts from the passengers side mount and when I pushed the engine up with the jack and took the mount off, it strip itself in HALF!!!!!!!!!!!! Immediately went to a NAPA and got myself a new mount and hey, THE SHAKING IS GONE!!!!!!!!! I just feel normal engine vibration now...normal for the 4.3L....

Almost $1,500 later it was only a freaking mount!!!!!!!!!!!!!!!!!!!!!!!!!
Swart, thanks for all your help trying to solve this man...I've learned a couple of neat stuff with your help...appreciate it...

 

I just went through the same ordeal. Shaking badly at idle after warmup.

Turned out to be a bad O2 sensor!
Not sure if there is a bigger issue behind why this sensor went bad or not but I guess I'll see if it messes up again.

 

Not a problem. I could have sworn that I had read somewhere that you had replaced the mounts so I didn't even suggest that. Even though I should have, considering the quality of aftermarket parts lately. Glad you got it figured out and fixed. That's the main thing.

Anyway, glad I could atleast help you learn some things, even if none of it really was the problem. I can't believe that the shops didn't check the mounts! I would be so PISSED if that's all that it was. What did the mount cost you? $60? if that? Alot better than the cushy hydraulic front mount on my Bonneville. I'll be replacing that one for a poly mount of my own design/construction this summer. That hydraulic mount actually limits the transfer of torque to the front wheels off the line and will hinder a launch at the track (where I plan to be a few times this summer for a baseline before upgrades).

 

The first mount I put in was a MOOG...never will try that brand again...I was thinking of buying the lower ball joints of that brand, BUT no way...I don't even know the brand of the mount I put in now, BUT what the heck...the shaking is gone...when I put the MOOG passenger side engine mount that's when my problems started!!!I spent about two hours doing this, but it certainly was worth it!

I really don't know why Precision Tune Auto Care spent 2 days with the car and found nothing wrong with it...thank God they did not charged labor, otherwise I would've spent a buttload o' money...