Gday, I just wanna run this past everyone to make sure my thinking is correct. Cylinder No5 doesnt make a difference when i pull the spark lead. when i check the plug its wet with fuel. I've checked plugs and leads and dizzy rotor. When its chugging away on 5 and i spray carb cleaner around the intake the miss goes away.

So ive got a manifold leak.

This only appeared out of the blue, I just finished wiring a rx7 fuel pump. I tested the pump on the car ran great. Wired it up so as to stop when engine dies. Then after that I started her up i started to get the got problem. I'm SURE the pump isnt the cause.

Manifold gasket is prolly only 4-5 months old (The exhaust place is like "nah get no problems with these gaskets" when enquired about it when i got extractors fitted)

So can a manifold leak prevent the firing of the cylinder?

Can it just sorta happen suddenly like that?

Is a 75 260Z Dome top Su's, 280zx dizzy and coil, mild cam, extractors with 2.25 exhaust. As of 3 weeks ago compression was an even 150 on all cylinders with throttle open.

Thanks for the opinions everyone

Luke

sounds like if they spark plug isnt firing and is wet hen u pull it out, the plug might be stuffed. How old are the plugs? Might be a good time to replace them ALL anyways now cos they arent too expensive.

Sounds like plugs OR Leads to me...

I just re-read my post - my english is bloody shocking! hmm....

If you are running carbs, and only one cylinder isnt firing, i think it is has a stuffed plug and might be running a bit rich which is wetting the plug (as you said) and thus not firing the plug.

As i rambled on about, replace all the plugs and see how you go.

Will work on my english..