Cold start rough idle and sometimes 303 code

[Lost1wing]

I wondered about a vacuum leak as well. Thought about giving a squirt of carb cleaner or similar around the intake to see if that changes rpm.
No additional codes, always the misfire......

Maybe you have a bad/loose engine ground causing a weak spark and the occasional no start. Funny how it showed on number 3 though.

I once had a similar issue on my 5.0 Ford. After exhausting all plugs and coils possibilities, I did a fuel injector test. I lost 75 rpms by turning off each fuel injector one at a time. However, one fuel injector only cause a 50 rpm loss. I replaced that fuel injector to correct the rough idle.

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[Hoist]

This was on my 30 min drive home. Probably 1000 plus of cylinder 3 misfires were in the first 5 min.

 

[Lost1wing]

Compression test or pull the valve cover.

 

[Hoist]

Roger that…….

 

[Stan H]

Cylinder nbr 3 is a smoking gun. Swapping coil packs and replacing sparkplugs would be a start. You could check the connections of the fuel injector for nbr 3.

This is the way !

 

[Hoist]

Ugh. Wish I could buy a new 1980 Scrambler…….

yes, I’ll be looking for a Cam plus parts. First picture is cylinder 3 fwd lobe. Might be hard to see but the groove is there.

 

[Hoist]

This is cylinder 5 rear lobe. It’s worse than three. Wasn’t getting misfires on that one but based on what I’ve read here that doesn’t mean it isn’t there.

sorry about the crappy picture but i have an old iPhone.

At least I have another vehicle to get to work.

Now to get on the list……

 

[Hootbro]

At least the problem is now known.

 

[ShadowsPapa]

\

The top of the intake lobe for 3 is worn down as well from the looks of that picture

 

[Lost1wing]

This is cylinder 5 rear lobe. It’s worse than three. Wasn’t getting misfires on that one but based on what I’ve read here that doesn’t mean it isn’t there.

sorry about the crappy picture but i have an old iPhone.

At least I have another vehicle to get to work.

Now to get on the list……

I hate it for you. It not what you wanted to see, but now you know.

 

[Hootbro]

Surprised this took almost 5 months to get here. @ShadowsPapa had the solid advice back then to pull the covers.

https://www.jeepgladiatorforum.com/...-sometimes-303-code.98017/page-2#post-1571756

 

[Hoist]

Yes, we talked about pulling the cover however after I changed plugs on the right side it improved until it didn’t. Changed driver side and it was good for a couple days then the low rpm stumble returned though not terrible. Did start the card in the bicycle wheel sound above 3 grand which was the final sign.

As much of a pain that was getting the cover off, I’m not sorry I took a while to get here. Who the hell puts that much plumbing and wiring over a valve cover?
i seriously considered pulling the water lines at one point but managed to pull em back far enough. I might consider some re routing of lines.

But, the good thing, as was mentioned i know the problem.

thanks for the TSB poop Sierra Pop!

 

[Hoist]

Surprised this took almost 5 months to get here. @ShadowsPapa had the solid advice back then to pull the covers.

https://www.jeepgladiatorforum.com/...-sometimes-303-code.98017/page-2#post-1571756

I hear yah, however it’s worth trying something easier first. This was THE worse valve cover pull I’ve ever done bar none. And I’m 66……..

 

[Hootbro]

I hear yah, however it’s worth trying something easier first. This was THE worse valve cover pull I’ve ever done bar none. And I’m 66……..

Be thankful, you had the easier passenger side bank cover.

 

[Hoist]

Be thankful, you had the easier passenger side bank cover.

Yah, hopefully the driver side doesn’t go.

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