How to diagnose and repair a miss? – 77 Jeep CJ

[Wendell]

So I’ve been helping my nephew work out a few issues with his 77 CJ5. When I got here it would not charge so we got that sorted out and replaced a gauge. Once that was done it was running great so he went ahead and changed our his worn our tires. Yesterday he took it out to run a few errands. When he left the store he was at he noticed that from the time he started it up it had a miss that hasn’t been there before. As he drove the miss seemed to get a little bit worse. The way he described it – at lower acceleration it wold miss real bad but when he would get on it a little bit and get into the higher RPM’s it would get better.

This jeep has the stock inline 6 258, 1bbl carb and points style ignition. The carb was recently rebuilt by a mechanic and has worked great since. The plugs are not fouled and the plug wires are relatively new – what is the best way to diagnose what is causing this miss and fix it? Any help is greatly appreciated.

Topic

[college man]

Check all the basics, points,cap,rotor,wires,Timing How many miles
on the motor? see if this link helps you.

http://www.ericthecarguy.com/faq/solving-automotive-performance-issues

[Bill]

Check the intake manifold to cylinder head gasket for vacuum leaks as it was a big problem on those engines. I’ve repaired many of them. Also check any vacuum lines and hoses running from the intake manifold for splits and leaks.

[EricTheCarGuy]

Yea, start with the basics, perhaps even a power balance test. The information in the article College man posted should walk you through it.

Keep us posted and good luck.

[Author]

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