2003 ram 2500 4x4 120k miles

i have a dead cylinder (number 6) 25-75 psi
replaced coil pack, plugs and wires with no luck
any other suggestion?

 

sumthin in your distributer cap?

 

None of those things fix compression. Either your compression rings are worn or you have a valve problem. Worn/bent valve or even possibly very dirty valve. I have seen valves held open by carbon many times on older high mileage vehicles. I'd try some Lucas Fuel Injector treatment in the gas and some Marvel Mystery oil in the oil and see if anything improves.
You can do a leak down test which will decipher if you have any leaking valves.

 

i've been using lucas in every other tank of gas. no leak down test yet, tkx.
it runs fine for about 15 seconds from start up then gets rougher the longer it runs.
could this be a computer ecm problem?

 

Again, Compression loss in a cylinder has nothing to do with the ecu. Maybe even a headgasket leak? I'd do a leak down test and see where that puts you. You may need a complete rebuild?

 

I did not say this before, but I drove it sunday and it ran great, monday morning it was broken...the more i drove it the worst it runs.
I also dont understand why it will crank and idle prefectlly for about 15 seconds and when start missing

 

Like Dog said, do a leak down test and see what you get.

 

I also agree with Dog as he is on the right track but also from what you are saying about it running right when first cranked but then later not running right could mean a crank somewhere and it opening up once it is warming up.

 

you mean a CRACK don't ya Weed?lol

 

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