ok now we jus got a bunch of snow so i was stuck. i had to do the forward an reverse rocking to get unstuck so after i got out my ses light was blinkin and i know that means somethin serious wrong check immediatly. so i back up plug in puter and it says p0300 multiple/random misfires. it didnt feel funny and it still seemed to be runnin jus fine no sputtering or stallin and it started jus fine to. so i shut it off and erase code and it started back up just fine. go to gas station right down the street and comin back bout 5 houses awaythe damn ses light comes on again but it aint blinkin its jus solid but same code. can anybody tell me what the problem is? its a 96 s10 4x4 "w" type engine that i just put in so all the plugs and wires and distributor and rotor are all brand new so i have no clue other than snow couldve caused condensation or somethin to that affect an got somethin wet and it caused a misfire twice. but i doubt that aint it it never is. so if some1 has a clue please let me know. thank you very much

 

in general tech i made a post of all the codes take a look for em

 

i know what the code means. i need to know how to get it not to come on and what made it come on in the first plase. all i wanna do is fix it and not have to worry bout damaging truck because i drove w that code or made it come on. whats the cause? and whats the fix? thats all

 

I'd pull the plugs again and check them. If it is misfiring enough to set a code, you should be able to see some abnormalalities on the plug that's affected.

Also, what brand of components (plugs, wires, cap & rotor) did you install. It is possible that you may have gotten a bad part. Even the best manufacturers can kick out a bad part every once in awhile.

At night, try spraying water along the full length of the plug wires. If there is an electrical leak, you'll see it! It is also possible that your cap is not sitting squarely on the distributor body. I would pull it again just to check things out inside and then make certain that it sits nice and square as you tighten down the screws.

There's more stuff to look at, but thats the basics. Cover them and I'll think on it a bit more. Good Luck

 

I don't see any reply or follow up on the p0300 misfire code. I have been chasing this code for a week since I fixed a coolant leak on a 95 s10 blazer 4.3 vortec which is a strange one due to change over to newer body style and update to mpfi from tbi. Several things happen on this blazer so for, 1-new thermostat, 2-new fuel lines(special order),3-new sending unit due to old one breaking off during removal to install new fuel lines,4-replaced rear end-some one must not have checked fluids and it set up,5-new alternator & battery. During this time the radiator was leaking and the guy I let drive it wasn't keeping good track and promised to repair but never did, when I got it back it was ran til overheated and had a broken lead from battery to alternator that the guy cobbed to get it running which I noticed while driving it back to garage, the dash lights (abs & brake) would come on and go out. The service eng light was coming on and started to flash so I knew I had trouble. Since this I have fixed the battery lead, replaced radiator, new plugs(autolight 605)after the parts store gave me autolight 25 which didn't looke right and seems to go to the pre 96 without vortec engine, this one is a 6/95 or like 96. I also replaced the wires and cleaned cap rotor-didn't replace yet as they look good and a new rotor looked worse. I also checked the car at night and no sparks flying around but idles rough and ses blinks and if you drive it it will go steady for a time till you idle. Any other ideas for me. I seem to smell a strong fuel or exhaust order with hood up but it may be normal and just me looking for things. HELP

 

Have you checked under the upper plenum to see if the Fuel Pressure Regulator is leaking? or the fuel lines to the MPFI (Spider). There a some posts here and on s-series.org that talk about rough idle and fuel smell.

Their fixes have been to replace worn parts in the fuel system inside the upper plenum...usually the FPR, and sometimes the "Nut Kit" or fuel lines to the FPR.

 

Thanks, I'll check plenum and FPR out. This code is a real pain to track down.

 

I have the same code that just showed up last night. If you ever figured out what it was, could you tell me.
Mine sucks in 1st and if I dont hit the gas to hard then the rest of the gears are fine.

 

Hi, sorry for delay in reply. I went thru all the usual stuff, plugs (twice),wires,cap rotor,fuel, intake gasket, did a compression test and found right side way under, pulled heads and it looked like bad head gasket(should have rebuilt heads)so replaced gaskets and tried again, no luck, still poor compression. Pulled head again and found 2 bend valves and 1 mushroomed. Had NAPA rebuild head and put back. Then it ran rough and wouldn't idle. Finally found EGR had carbon even after I cleaned it, a piece must have broken loose and stopped EGR valve from working. Runs strong now. It takes a lot of time and testing to find these problems, good luck.

 

Dang that sucks, because my blazer is my DD and I dont own anymore cars(just sold 3).