hey guys im new here, i've been reading around on the site quite a bit trying to find a fix for my problem but now i need your help... my truck (97 ram sport 1500 5.9 4x4) is throwing a CEL.. at first it was cyl #8 misfire. then random cyl misfire. its driving me nuts! so far i have replaced the spark plugs, wires, cap, rotor, and the pick up coil. its got good spark, just a little bit of a miss. oh and i did a compression test and number 8 only had about 80psi, and a tablespoon of oil in the cylinder didnt help raise it.

now mind you its always been in the back of my head that this thing had a cracked head... basically the guy i bought it from blew a headgasket a while back. he drove the truck on its last leg for a few days, it would turn over and jam to a stop, since water doesnt compress i could see that causing some issues... so anyway he went in and replaced the headgaskets, i am fairly sure he never took the heads in to get checked. so once the truck was back together and running again. it was running rough.. not really bad kinda sounded like it had a cam in it. so now i've had the truck for about 4 months now and its been an awesome truck, other than running a little rough, well finally the CEL came on a few days ago and thats when the fun began..

what do you guys think? i found a rebuilt set of heads pretty close from a private seller for 250 bucks... im debating on just tearin the heads off and doing new gaskets again and sticking these on...

 

Plenum is blown(do a search here on DF for that), precat o2 is bad and the cat is clogged.

Welcome to DF btw.

 

the cat is hollowed out. and if i get the heads from this guy i will buy a whole gasket set, but i do not see any oil down in the intake and my plugs dont have any oil on them...

do you guys think i should buy the heads?

 

It's quite possible the pieces from the cat have clogged the muffler too. Either way, the lower intake gasket needs to be checked. And depending on how the cat was gutted, the o2 might have been damaged in the process. Also, depending on how long the cat was originally clogged, your right about the head crack, but also the valves can be damaged or have a lot of carbon built up.


edit: you just looking through the butterflies, or did you remove the TB and check with a mirror and light?

 

i took the throttle body off, and looked inside with a light and mirror. when i hollowed out the cat because i knew it was clogged up i took the 02 sensor out, the insides fell out in about a million pieces. im pretty sure the muffler isnt clogged because the truck sounds ALOT better than it did before the cat was done. and, since the muffler is just clamped on i even tried removing it to see what it would do... nothing really different just a lot louder. i've been all over the internet trying to find fixes for my issue. ive done everything from the tsb on running the plug wires to having the code pulled which, i dont remember the code now but it said cmp sensor was bad which turned out to be the pick up coil in the distributor. i have ran seafoam through the intake twice now and let it sit there for 15-20 minutes each time and nothing changed... cleaned the throttle body with TB cleaner when i had it off..

the heads i found are from a 96 5.9 magnum, and mine is a 97 5.9 magnum. i and beginning to think thats my prolem, but i dont want to replace the heads if there is a chance it is something else... i just cant find any other possibilities...

 

not sure, i've never replaced it... they are fairly cheap, woult that throw a misfire code? but what about my low compression? shouldnt it be up around 150 160?

 

Heads are exactly the same. No worries there.

How old is your O2 sensor?

 

and make sure you didnt use bosch spark plugs.. .. I fought with mine for 2 weeks.. trying to get rid of a miss..put champion plugs in it..runs great

 

had autolites in it before but i has champions in it now.

 

i had the same problem with the autolite 3923's. stock champions run great.