dead miss

[82BlazerMan]

1982
Full size Blazer
305 ci
carborated

I've got a dead miss in #5 cylinder.  I've checked the spark and it's getting good spark.  The plug looks good too.  I've had some vacuum problems in the past and I'm thinking it's a vacuum leak, although I've checked all that too and it seems good.  I'm not expert, but is there a way to bypass vacuum down to the basics to see if it's causing the problem.  Or check this out, could it be a gasket leak in the intake or the heads causing it to leak vacuum and miss?  

[VileZambonie]

Do a compression test.

[barneyb1]

i had something like that and i had a rocker arm come loose
i let mine sit for two years because i thought it was fatal

[Lt.Del]

Vacuum would not make it miss in only one cylinder.  As Vile stated, a compression test in all cylinders would show if there is any loss of pressure (due to head gasket or broken rings, cracked head, etc) in any one cylinder.  

You said the spark plug was good, did you change it out and retrest?  I would put a completely new plug in it and wire from distributor.  Check out the distributor cap and ensure the the little nipple for that cylinder is ok....just replace the cap anyway.  

SgtDel
aka "Andy"

www.delbridge.net

1979 Big 10 383 stroker
1991 Blu 'Burb 3/4 ton 4x4

[82BlazerMan]

Did'nt do the compression test cause I don't have a tester.  I did remove all lines except the pcv and advance and low and behold, the miss went away.  Now all I have to do is put them back one at a time and narrow down the culpret.

 

[joesgarage71]

You can also use WD-40 to find a vacuum leak. Slowly spray in the suspect areas (W/engine idling)when the engine idle clumbs you found it.