Hey everyone, don't hate me for posting before searching but i really need some help here, (I will search after i post, probably all night). Anyway I was driving from SLC, UT to Boise, ID and a couple hours into the drive the engine started acting strange. The best way for me to explain it is, on old 2 cycle engines when you start them cold, if you give WOT at first the engine just boggs down and won't go. That is exactly what is happening, if i put the gas pedal to the floor the engine just boggs down and slows me down immediately. Sometimes it is only at full throttle, and sometimes it is half to full throttle. After a while of driving the CEL turns on and then the engine runs perfectly normal. Then after a while again the CEL will turn off and the engine will start acting up again. So in the end i did make it to boise, but i do need to get back to slc this weekend. So I need help on a few things, first there is no ODBII port on my rodeo, so if anyone has the information on how to get the CEL code that would help a lot. Second has anyone had this problem before or have an idea of what it is? Oh one more thing that might help diagnose the problem, whenever it boggs down i see dark black exhast coming out the exhast pipe.

Any help would be greatly appreciated!
Thanks!

1996 was the first year that OBD II was the on board diagnosos standard. The OBD II port should be underneath the fuse box on the driver's side (you have to look directly up at the bottom of the kick panel to see it).

Well, i think it is a 95.5, manf. date was 10/95. Either way it doesn't have the port, I have a 97 rodeo as well which has the port, and i have torn off all the panels on my 95.5 on the drivers side to see if the port got pushed up inside the panels and couldn't find it.

For a pre-OBD II vehicle you need to short together pins 1 and 3 on the data link connector, turn the key to the "ON" position and count the CEL flashes. Code 23 will be FLASH FLASH... pause... FLASH FLASH FLASH. Then go here to decipher the code.

I found that last night, but where is the data link connector? I took all the panels off this morning on the driver's side. I have 2 3 wire connectors, 1 2 wire, and 1 single wire connector.

I would still like to read the codes so if anyone has information on how to do it on a 95.5 it would help. But for now maybe someone can help troubleshoot. From what i've read the most common problems for this are: o2 sensor, egr valve, and a long shot of battery?. I read the stuff i could find on the egr valve and how to clean it, but i couldn't find it on my engine. Also I got under the truck and looked for o2 sensors, it looks like mine only has one sensor which is before the cat. The only reason i put the battery in here is cause it looks quite old and the connections are corroded, but it still cranks fine, so i'm not sure if that is a possibility. Anyway, my trip is supposed to continue in McCall about 120 miles away, so i would really like to get this figured out this morning so i can get up there.
Thanks!

FIRST OFF YOUR TRUCK IS AS YOU SUSPECTED A 95.5 SO IT WILL NOT HAVE A DATA LINK CONNECTOR LIKE THE 96 PRODUCTION FOR 96 VEH STARTED 11-95 , THE SYSTEMS YOU DESCRIBE SOUNDS LIKE YOU HAVE A BAD 02 SENSOR , CEL INTERMITTENTLY AND BLACK SMOKE , AND BOGS DOWN. THE CONNECTOR YOU ARE LOOKING FOR IS THE WHITE 3 PIN , WITH A SHORT JUMPER WIRE CONNECT THE TWO OUTSIDE TERMINALS 1AND 3 TOGETHER WITH THE KEY AND ENG OFF, NOW TURN THE KEY TO THE RUN POSITION AND THE CEL SHOULD FLASH THE CODE THAT IT HAS STORED, IT SHOULD FLASH 12 THREE TIMES AND THEN THE FAULT CODE OR CODES WITH THE LOWEST NO, BEING FIRST AND THEN ON TO THE NEXT . NOW AFTER YOUR REPAIR YOU MUST CLEAR THE ECM OF IT,S STORED CODES ,TURN OFF THE KEY REMOVE THE JUMPER WIRE AND DISCONNECT THE BATT + TERMINAL, NOW WITH THIS CABLE DISCONNECTED YOU CAN WAIT ABOUT 5 MINUTES TO CLEAR THE ECM, OR YOU CAN TAKE A JUMPER WIRE AND DO IT THIS WAY TO GUARENTEE CLEARED CODES , BUT LISTEN CLOSE TAKE THE JUMPER WIRE OR USE THE +BATT CABLE THAT IS DISSCONNECTED FROM THE BATT IF IT WILL REACH AND HOLD IT OVER AND TOUCH THE GROUND CABLE AND HOLD IT ON THE GROUND POST , WHILE DOING SO HAVE SOMEONE TURN THE KEY BACK TO THE ON POSITION FOR JUST A SECOND OR TWO IS ALL IT TAKES , TURN THE KEY BACK OFF AND HOOK THE CABLE + BACK TO THE BATT ,THIS WILL CLEAR ANY AND ALL MEMORIES IN THE VEH, RADIO OR WHATEVER JERRY

Jerry you are awesome!!! Thank you so much! My wife says she wants to send you cookies! So I got the code it is 44 which from what i have found is "O2 sensor lean condition detected". So i assume i just replace the O2 sensor? Thanks again!

I used to get that code all the time when I had exhaust manifold leaks. Air enters upstream of the o2, ecm thinks engine is lean, richens to compensate, richens beyond acceptible limits then goes into "limp" mode because it knows a problem is present. May not be your 02 sensor. Although this is how it worked for me, may not be your situaton. fyi my engine always ran fine, no bogging during this, just a cel light.

THAT IS A HEATED O2 SENSOR , before putting in a new one try this, pull fuse no 6 and see if it makes any diff , this is the fuse to the heater in the o2 sensor, if the sensor shorts internally they will do some strange thing s and it is not uncommon , they can drive the eng rich or lean, if no difference just unplug the o2 sensor , this will throw the eng in to a fail safe or limp mode as it is called,and the ecm will ignore all but 2-3 input signals ,the eng will run fairly decent but you will have a cel on, allso don,t forget the fuse it controls the wiper frt and rear and the washer Jerry