Per your recommendations (thank you!!), I did a test where I removed one spark plug cable at a time out of the distributor to see if it affects how even the motor runs. All of the spark plug cables make a difference and the motor shakes/vibrates except one. The one that doesn't make a difference does have a spark when I try the test where I remove it and leave a small gap and watch the spark jump from the distributor cap to the spark plug cable. I took the heads in before I put the car back together and they machine shop guy said they were good. My car runs and everything, but when I accelerate it isn't as stong as I think it should be. What could be the cause, how can I test it out to confirm what's wrong and then how do I fix it? 302 motor 4 barrel carburator Thanks for any advice!!
try swaping the spark plug with another cylinder and see if the problem follows the spark plug or stays with the cylinder. if it follows the plug then you just need a new spark plug. if it stays in the cylinder then most likely there is a valve problem on that cylinder. put a valve cover off and make sure the vavles are properly adjsuted.
i think is a I think is a valve problem!! do i have to replace the valve now? what do you suggest? thank you for your time!
Don't jump to expensive conclusions without checking all the possibilities first. Accurate diagnosis can save you a lot of time and a ton of money. Find out for sure what the problem is!
So what else can it be? I just changed the spark plugs, a better ignition coil , performance gas pump, and i just checked that the valves are adjusted properly.
Do you have a simple compression tester??? If so check the suspect cyl. If it reads bad...(low or no pressure) its a valve or piston/ring problem. Did you replace the spark plug on the suspect cyl??? If not, do this before you go any further. Could be a bad plug. Is this spark plug particularly difficult to install??? Its possible you bent the ground electrode over or got crud in the gap while trying to fish it into the hole. You could also have a cam with a bad lobe on it, or a bent pushrod/broken valve spring, even a cracked rocker arm. You need to do a really thourogh visual inspection of the component on the suspect cyl. Could be a bad plug wire too...Try pulling the wire at the spark plug and see if the spark is makeing it that far. Good luck man!!!
It could be a bad plug, rocker arm, or pushrod to name three. Start by pulling the plug - if it looks good try changing it with another one. Try swaping the wire to that plug with another one. Check the cap for carbon tracks. Have a leak-down test performed - that will tell you if the valve is leaking or if the rings are.
