#1 and #4 are dead ??...

Plugs failing under compression? I hate the WAG system, but they're cheap to replace.

I stuck a plug in it from the old tune up, nothin' doin'... Of course, that plug could be failing also. Since I will be replacing them during this heavy maint session anyway, I may install two new plugs and check it again.
I just can't see anything ? I pulled the bulkhead cover and shot it with starting fluid all over the front of that engine ?? I can.t find anything.

Just remember George Holley's famous quote (recorded on Thomas Edison's Gramophone) when he was fighting with Henry Ford over the integration of first "Iron-Pot" carburetor on the Model T....

"Henry - I am telling you! 90% of 'carburetor problems' are ELECTRICAL!"

Rocky

It has a new cap/rotor/wires and was running fine... It's a daily driven car and has been running very well for about four years now. Just usual maintenance, tune ups, oil changes and rear tires...lol...

...You say the Plug Wires are New.
Did the problem start After the New Wires were installed?
If so, check the resistance on the wires, And could the #1 and #4 be switched??
Double check the Firing Order, mis-placed wires happen all the time.
Do you have the Correct Spark Plugs Installed?

I did the cap rotor and wires about two months ago, it has been running fine, I even harassed 15' vette and stayed right there w/him. I have been running E3 #42, I'm not sure they are the best plugs but they have been working ok for me. I just don't know ?? I'm gonna clean it up some more and see if I can find something ??... Leave it to me to have the goofy issues...lol...

Remove spark plugs "1" & "4" from the cylinder heads, ground spark plug to the engine block & turn over the engine.

Are you getting spark to both plugs?!

Yeah, I have a spark tester... both good.

...Since you have the plugs out, do a Compression Check. No compression and the Dead Cylinders won't Fire.
Is there Water in the Oil? Or Oil in the Water?
Let's hope it's Not a Blown Head Gasket!

Yeah, I guess I will put her up on jack stands and give her a once over... I'll check all the cylinders for compression. The oil looked good. I pulled in the night before and everything was fine... Next morning she was not happy.

To check for a vacuum leak on the under side of the intake manifold, remove the PCV valve from the valve cover and seal the valve cover opening.

Remove the cap from the other valve cover and start the engine.

With the engine running, place a business card over the opening in the valve cover (where the cap was removed).

If the business card is held in place by a vacuum, then you have a vacuum leak from either an intake manifold gasket or a cracked intake manifold.

John

Thanks John!... I have it all apart now...lol...

quote:

I have it all apart now

Any sign of the gasket leaking?

John

I only have the plugs out and valve covers off. I am going to lift it and go over it asap... Stay tuned !...

It can only be one of 3 things, air, fuel, spark.
It sound like spark, switch out wires that are currently working with their plugs, good luck.

I'm confused by your approach

Did you confirm that ALL spark plugs were firing?!...prior to removing valve covers & intending to remove the intake manifold.

You don't need "fuel", "air", nor "vacuum" to fire a spark plug!

I did check all normal stuff, and it is possible of course that I missed something ( I almost always do )... I just did a run down of the usual suspects, it has spark, the plugs are E3 #42 with about 8K on them over the past year, I inspected the vavletrain and found no issues, I rotated the motor and all the rockers are working and locating correctly, I checked the wires for correct placement ..??? I did not try Johns vacuum trick w/the business card though. I guess I kinda' want to pull the intake and give the top a once over, I have driving the car for about three years and I literally have not touched the carb. I'm gonna' pull it all apart, clean it all up and reassemble. She's been a good car, no a great car! I beat on her constantly, she see's WOT at least 5 times a week, all I do is service her and buy rear tires...lol... I owe it to her. I'll tell ya' what will make your car feel slow, having a much faster car sitting next to it, I do not spare the whip and she really has been good to me I will report back...

The issue here is clear to me... The Pantera clearly feels emasculated by the bird car cruising around topless and having his junk all hanging out. Crap man....how would you feel if that was your roommate? Good luck feeling good about yourself.....

Ok...so I'm struggling with the binary element of this challenge. It worked perfect when parked. Definitive statement. Therefore, I'm struggling thinking it is any kind of deep engine ... "hardware" issue. (i.e. vac leaks, bad gaskets etc etc). I would think it would be more of an electrical issue. Thoughts:
- did you put a timing light on each spark plug lead to confirm each plug was firing correctly/not? I imagine yes, based on your thread title, but worth confirming.
- what is the ignition system?
- I think fuel is out, if you have confirmed it to be specifically two cylinders.
- I'm with speed, it seems like it plug fouling would be a likely cause....

Yeah, I found it a bit odd myself. Although I had just thrashed the car within a few miles of the house. I agree, I just don't see what could happen to a car sitting there over night.
I guess it's important to mention that for about a 1000 miles now I have been saying things like "ok, this is my last tank of fuel and I will pull her down for some heavy maintenance" and " OK, she needs rear tires I'll just stop driving her and work on her"... But that never happens, I just can't leave her alone... But now, she's running like crap and I am properly motivated! I will clean and check everything up top. I have the MSD 8950 I think it is and I mounted the box inside the car so it gets a/c... I will pull it apart in the morning... I may put it back together and do one more testing session first... Stay tuned...

OK well... I don't know what the hell happened here... We pulled the deck lid off and I was about to pull the intake when I decided to put it back together and do a bit more snooping around. We put the plug wires back on it w a new set of plugs and she fired right up and runs good. I have had plugs fail under pressure in two strokes but never in a car ? I change them at least once a year usually more. The only thing I can say is my spark tester confirmed huge spark on 1 and 4, but when I assembled the car - ice cold pipes! Ok, well... Thanks you guys, I appreciate all your help. This is another in a long line of events over many years indicating, nay confirming I am sort of a dumb ass.... Thanks for helping me you guys !...

Guaranteed those amongst us that are "Honest"...have worn the Dunce cap MORE than once

It's ALL a learning curves, some curves are navigated smoothly, whilst others land one squarely in a ditch!

I had all kinds of problems with my car this past summer too . broken drive pin on distributor .The harmonic balance spun on rubber very hard to time the car like that , Also the wire feed the coil was no good checked with test light looked good but car would not run right . but car started up I run car for couple month, when lugging motor car would shake like crazy. check and re checked every thing ran great other wise .just found problem the other day plug number one was not on plug but pushed in next to it . funny things can happen.

I guess... two plugs failed under compression, over night, right across from each other ??...

Odd, unlikely, but I checked the wires and they had great spark but the pipes were cold...

I changed all the plugs and she runs good...

good to hear..! Glad all is good.