Cylinder 1 Misfire

[tj johnny]

Greetings all:

I scrolled a few threads but didn't see the answer I need - which is, from wherever you are, accurately diagnose my issue . 1998 TJ, 4.0, with an intermittent Check Engine light. Local parts store code reader says misfire, #1, with a recommended fix of replace valve springs. I suppose, but doesn't strike me as the most likely culprit. I can feel the occasional miss under load. Is this a common issue? I have to get that cleared up so I can pass a smog check in the paradise that is California.

 

[Chris]

Valve springs and a misfire don't really go together. Can you provide us with the exact code that they pulled from the reader?

 

[Chris]

By the way, this thread may be related to your issue:

https://wranglertjforum.com/threads...-for-misfire-at-idle-or-low-speed-only.64102/

 

[tj johnny]

Valve springs and a misfire don't really go together. Can you provide us with the exact code that they pulled from the reader?

Now that I can't find the paper they gave me, I believe it was P0305. I feel the occasional misfire usually going from a stop and revving through 1st gear.

 

[tj johnny]

By the way, this thread may be related to your issue:

https://wranglertjforum.com/threads...-for-misfire-at-idle-or-low-speed-only.64102/

I read that one but I don't have any obvious indicators of this being an issue, like constant misfire, overheating, etc. I'm really hoping it's not something as involved as this..

 

[Chris]

I read that one but I don't have any obvious indicators of this being an issue, like constant misfire, overheating, etc. I'm really hoping it's not something as involved as this..

I would definitely start with a leak down test to rule out the cracked head. Also, pull the spark plugs and inspect that one. Post some photos so we can see what it looks like.

 

[AndyG]

The first thing I would do is check the condition of the spark plugs and plug wires.

This is a 24-year-old vehicle- You would be amazed how many are still going that have never had a tuneup.

The 4.0 is one of the most indifferent engines when it comes to lack of maintenance- It will eventually do what mechanical things have to do but it will just amaze you at the abuse it will take

 

[tj johnny]

The first thing I would do is check the condition of the spark plugs and plug wires.

This is a 24-year-old vehicle- You would be amazed how many are still going that have never had a tuneup.

The 4.0 is one of the most indifferent engines when it comes to lack of maintenance- It will eventually do what mechanical things have to do but it will just amaze you at the abuse it will take

Yeah, I'll start there and then try a leak down. I did a complete tune up a few years ago with new from the dist. cap to the plugs after I got this thing from my sister. She was a put-gas-in-it-and-drive-on kind of owner.

 

[pagrey]

If the leak down is bad try the de-carbon process dumping water in the intake with the engine running, can't hurt. Plenty of threads on that process.

 

[tj johnny]

If the leak down is bad try the de-carbon process dumping water in the intake with the engine running, can't hurt. Plenty of threads on that process.

I may try that. What's the product you can buy to poor into the intake? Makes smoke like crazy but I've seen where people swear by it...

 

[AndyG]

I may try that. What's the product you can buy to poor into the intake? Makes smoke like crazy but I've seen where people swear by it...

I think its SeaFoam but don’t hold me to it.

 

[tj johnny]

I think its SeaFoam but don’t hold me to it.

Yes, that's it!

 

[Jerry Bransford]

I'd be willing to bet using Sea Foam for this problem won't do a thing.

 

[tj johnny]

I'd be willing to bet using Sea Foam for this problem won't do a thing.

Have you ever used it for anything? I've seen the YouTube videos where the engine "magically" improves.

 

[tr21triton]

like AndyG said check your plugs ! how many miles does it have on it ! use autolite XP-985 plugs in it !