sporadic misfire

[greenmonster]

I have a misfire that I can't track down.It is from idle-2500.It makes a puffing sound from both sides of the exhaust.It feels like a dead cylinder,but it moves around.I put a vacuum gauge on it and it is steady at about 20in.Any ideas would help.

[Irish_Alley]

True duals

[greenmonster]

Yes,true duals.

[Laderhosen]

Are your header bolts tight??

[greenmonster]

Yes they are tight.I just switched headers 2 weeks ago,but I have had the problem for months.

[Lt.Del]

common diagnoses tried yet?  wires, plugs, cap, rotor?  Got a temp gun?  point it to each cyclinder at header and see if one reads much lower.  These temp guns (usually w/ a red laser) are very cheap.  I use it for a lot of things.

At night, no light, idling, pop hood, any sparks from wires?

[greenmonster]

I put a full tuneup on it,and it didn't help.I even tried a different distributor that a friend had.

[1980c10]

Try a compression test.

btw sgt
"At night, no light, idling, pop hood, any sparks from wires?"
I did this and my wires were glowing blue.

[greenmonster]

I done a compression test 2 months ago,and it was fine.

[topp]

If the symptom wasn't there 2 months ago, the test would be good......
If this started since then, the test is needed

[greenmonster]

It's been like this for 6 months.It was running great,then one morning it started acting this way.

[TexasRed]

Fuel filter good?

[greenmonster]

I replaced that too.I pulled a plug and grounded it out and the spark is orange.Is that normal for hei.

[Irish_Alley]

It should be blue. Where did you ground it to?

[TexasRed]

You have 12 volts going to the distributor?