Missing/miss fire problem..

Lately Ive developed a missing/miss fire problem. Engine is a 302. At first it was only while I was in park, at a rev around 2 grand...sometimes a little miss/pop driving down the road. I was going to check it out this coming weekend but...I hopped in the truck to grab the fiance and me something to eat...first gear, and most of 2nd gear was nothing but cutting out from how bad she was missing. I recently changed out the plugs, the cables, and the cap and rotor, so those shouldnt factor in. ANY advice is appreciated! Thank you!

 

A couple things I would look at, First check if you have anything arcing under the hood like a spark jumping across something. I'd also check the timing and try to adjust that to see if that helps. Sometimes if the timing jumps irratically, the timing gear chain may be getting loose and jumping a tooth. Pull the fuel pump and you can check the chain for looseness. I'd pull a plug and see how it looks as well. That will tell you how the engine is burning fuel rich or lean condition.

 

Ive been meaning to check the time anyhow, because Ive had a feeling about it because..every once in a while/lately, its been starting odd..sometimes it would fire up within the first 1 to 2 times of turning over..sometimes it would turn over 4 to 5 times, and even sputter before starting. As far as the fuel pump, its keeping fuel in the fuel filter, so I dont think the pump is weak/going out..?

 

if you are using points ignition i would check the condensor.

 

...I didnt think of the condensor. What about the pick up..? Would that be going out?

 

Most of the above is the last thing that I'd do. The tip about looking for something arcing is a good one, best done at night.

Make sure your coil wire is all the way in. Pull it out and look at the end and the tower in the cap, any signs of arcing there, replace the wire and cap.

Aside from that, go with changing the points and condensor. Look at the inside of the cap and tip of the rotor, I've seen new ones of each go bad out of the box.

Bob

 

Open the hood and check for arcing. Do it in the dark, Check around the Dist. area then the wires and at the spark plugs. If there is any arcing that would be what I would change first. If not check to see if all the wire are tight in the cap and the coil.

after that I would check the coil. If the coil is ok. pull the cap and look for cracks or carbon trails on the inside of the the cap. Check the points to see if there burnt and set right. ford points will wear if you do not use lube on the cam in the dist. Also check the condenser.

If every thing is ok check the dist. for play in the shaft. If there is a lot of play it will change the timing. Check the points at the tip of each cam lube. If there more then .002 difference the cam could be worn.

Timing should be set at 8 degrees BTC.

If all of that is OK. Check the plug wires with a ohms meter.

 

Need more info. Carb? EFI? Points or electronic ignition?
Sounds like bad plugs. Even new ones can be bad.

 

Carb, and points.

So, I might have some new thoughts on the situation as well. I had some wiring problems a while back, and I replaced the coil. When I replaced it, I just picked up a house brand from O' Rieleys. Point being, its not exactly a performance part/NOT very heat resistant..lol! My coil is mounted to the block, and it gets DAMN hot QUICK! I know this can screw the spark up. When the coil gets hot, that when I run into problems most of the time...I just didnt figure it would make the engine miss as BAD as it was..? Any thoughts on that?

 

To add to that. I didnt really have any problems with the heat last year..just a little spew out of the over flow. Point being, I didnt have the coil that I have now.

 

do you have a coil resistor?

 

Don't forget to check fuel. A clogged fuel filter will do that.