i live in cali
bought a 97 dodge ram 5.9l with aprox 155,000 miles on it.
took it home and 1st night ran great was so happy 4x4 extended cab
paid 4,000 cash. next morning i go to start it and get check engine light but it does start has a sputter.
long story short
cyl 5 misfire
not plug wires dist cap or rotor nor injector
only 105psi on cyl 5

soooooooo valve rings or cam pic your poision bunch to fix
1000+ more than likly i called the guy up he does not care but it wont pass smog i cant even put it in my name he says ill get it to pass smog.
so lets pretend i paid 1200 to get it fixed what break next what else is hiding
what would you do.. i love the way the truck rides power it has a bunch of power motor runs good.. would you let the guy smog it knowing running the motor will screw other stuff up im not mechanical inclined. i thought change a dist cap was pritty amazing. i priced checked a rebuild motor its 1800 . it took everything i had to pull togather the 4grand please give advice.

 

that was really hard to read. don't be afraid to use a little punctuation every once in a while.

so what are your compression readings on all 8 cylinders. 105 is some low, but its not that bad. also what CEL codes do you have? autozone style parts stores will usually read the codes for free. if they do write down the codes themselves and post them back here. don't just come back with autozone's interpretation of what the code means.

so how's it running at cold idle, warm idle, and out on the road ? good, fair, poor or what? is it real bad, or just a little rough idle ?

 

the compression readings is only on cylinders 5 and 7. 5 was at 105 and 7 was at 137. what is a cel code? my obd2 says code p0305. at a cold idle is a 80/20 chance 80 percent it will idle rough and the other 20 percent it will idle fine at a cold start. After warming, it will be more of a 60/40 split any throttle cold or warm takes the roughness right out of it and some times it wont come back.

 

CEL is check engine light. same thing as OBD. p0305 is misfile on cylinder 5, which you already posted.
you can reset the pcm and turn off the cel by disconnecting the negative battery cable and turning on the headlights for 30 secs. but, if you do that, you'll have to drive 50-100 miles for your truck to record enough data to pass your calif emissions test. i assume the truck also won't pass with the cel on.

so you've already tried plugs, wires, cap, rotor.... all with no change.
what you do with the injector, swap #5 with another cylinder, or did you replace #5?

what i'm wondering the most - is how did it run fine for the first day, and then begin to run poorly ?
maybe the pcm was reset right before you bought it, and maybe it runs good at default settings and then begins to adjust leaner and develops the problem ? anyone else think that possible?

without any better ideas, i'd reset the pcm and drive it some to see if it comes back. maybe get out on the highway and run it some at 60+. if the light doesn't come back on then whip into an emissions check and try to pass.

 

105 is kind of low, but not low enough to cause a misfire. I'm not saying that #5 isn't misfiring or that something is getting tired for that cylinder, the code proves it is, but I don't think your compression reading is the real problem. Reading your original post it sounds like you replaced most ignition components and the injector. If you haven't do that first. If all that checks out it could be a wiring problem with you injector wiring (broken wire so the injector isn't grounding causing it to spray fuel), could even be that your computer developed a bug. Do like dhvaughn recommended and reset your PCM

 

Kiznar...if it won't pass smog, and he DIDN'T sell it to you as a PLANNED NON-OP, then either take him to small claims court for your money back. He's suppose to pay for anything that needs doing in order for it to pass smog.