misfire po300

[jpmxrider489]

OK I been chasing this misfire for a while now. This all started after I did the jmf intake manifold install. I did research and most threads I find are people having a non 95 CAS. I have a jmf coil relocation bracket and the harness is under the manifold. But a little background. I originally had a COP and then sold it because I didn't have a the correct setup. So went back to the coil. After a while I got a code ( not po300) but a misfire code. Noticed my coil was bad. It was sparking from the coil. So once I saw that I replaced the coil plugs and wires. I have the ngkbpr7 and ngk wires and oem coil. The coil and wires and plugs looked fine. I swapped them for a buddy's parts and still the same problem. So I put my parts back on which are a year old. Also the transistor is fairly new as well. I replaced that 2 years ago. As most of you know, The smim deletes your EGR. I don't know if that is important to my issue. But to my knowledge I did what I know. I did a boost leak test as well and fixed them all. Could it be the CAS? Im just totally frustrated. Please help.

Could it be bad gas? I drove it for a while with the gas that's in it. I cant see it being bad.

 

[1davho]

Are you running dsmlink? If you are, check the tab to ignore the misfire code and see what it does. I know if it thinks its misfiring, it will start cutting fuel to the injectors.

 

[lee98talon]

i just read some where the other day that the code P0300 is multiple misfire code and code P0301 will mean misfire in cylinder 1 and p0302 will mean misfire at cylinder two and so on. just a fyi, incase you didnt know. And please correct me if im mistaken. and im having the same problem, too. but still working on my. tested my coil pack and it show 1.2ohms on one and 0.9ohms on the other. is that bad result because its pretty close to spec ?

 

[1davho]

I would say your coils are good. I would check the gap on your plugs and make sure your transistor is plugged in all the way. The clips are always broke on those and if it comes loose it will cause it to drop spark to two cylinders. And as for the individual misfire codes, the computer has no way of really knowing which cylinder is misfiring so its not always missing on the cylinder that it sets a code for.

 

[doubleclutch]

Having the same issue with the same parts replaced (coil, transistor, plugs, wires). They are gapped correctly.

Does your car stumble real bad or just have the code and drives ok?

 

[jpmxrider489]

It seems like this all happened after my smim install. But coil is new. Plugs are new and gapped correctly and wires are new. I replaced the transistor when I did a head gasket so it should be good. The only other thing I can think of is bad CAS. I have a 95 so its under the cam gear. Also the fuel filter is new with the fuelab.

 

[jpmxrider489]

So im going to bring back this thread from the dead. I'm still having the same issue. I fixed my idle problem. i have link so my idle is almost perfect. So I went to do a cruise log and i got the po300. As I said above everything is pretty much new. Does anyone no how much amps/ohms that the coil and transistor is supposed to be? Ill check that next. Also When I did the jmf intake install the map sensor is now hanging. Do I need to do something with that? Also Is there any little ground wires that were hooked to mounting bolts that I could be missing?

 

[jawar666]

In the DTCs tab in ECMLink there's a checkbox to tell the ECU to check for cylinder misfires... uncheck that box and save....

I had the same problem a couple of years ago using a 1G CAS with a 95 Non-Eprom ECU and it was almost impossible to fix.... I was able to "reduce" the problem when I tried with a 97+ CAS instead of the 1G CAS...

I hope that helps you....

 

[dsmAB]

I had a similiar problem, and i also own a 2ga 4g63t talon which the cas was behind the cam gear. I replaced the CAS and it fixed my misfiring problems.

 

[jpmxrider489]

So I drove the car for a bout a 15 minute cruise after I unchecked that box. It didn't give me any issues. But It did seem to try and misfire but it seemed to correct the issue. But I am curious to if my problem is fixed or just a band-aid. Any one can please give me insight or opinions?[DOUBLEPOST=1408530743][/DOUBLEPOST]I drove the car again and still seems fine. But what do you guys think?