P0300 ( Random Misfire)

Took care of my previous problem and now I'm getting this code.:mad: Just started today. My mechanic is out of town til Friday the 19th,so I was going to try to find out what I could find out myself. Here's the freeze frame data if it will help.

Fuel system 1..............closed loop
Fuel system 2..............closed loop
Calculated load..............2.3%
Engine coolant.............195 degrees
STFT Bank 1........................3.9
LTFT Bank 1......................-7.0
STFT Bank 2.......................-3.1
LTFT Bank 2....................... -3.1
Intake Manifold Press...........12.4 in.hg
Engine Rpm........................571 rpm
Vehicle Speed.....................0 mph
MAF sensor........................000.91 lb/min
TPS..................................0.0%

come on Injuneer,where you at?

Search for P0300, and you'll get lots of hits, but few solutions. Mostly likely causes are bad wires or plugs. Maybe opti. An enhanced OBDII scanner should be able to pinpoint the cylinder(s).

vacuum leaks are common cause of random misfire at idle

Well,
Now my previous code(P0172) has come back.:mad: Could it be that I have a bad wire,plug that isn't firing causing a rich condition because the fuel isn't being burnt then in turn cause a misfire code?

list of mods might help..........

list of mods might help..........

Car is stock.

Just got my car back from my mechanic and he replaced the plugs and wires. Still have the misfire code,but he says that the optispark is bad. He can't change it til next Thursday. He's going to fix it for me for around $260.00 installed. Sound about right? I don't have the time to do it myself.

Just got my car back from my mechanic and he replaced the plugs and wires. Still have the misfire code,but he says that the optispark is bad. He can't change it til next Thursday. He's going to fix it for me for around $260.00 installed. Sound about right? I don't have the time to do it myself.

The opti itself will several hundred dollars depending where he gets it from. 260.00 will be for just the labor most likely. It almost sounds like he is guessing his way around the problem, I hope that he doesn't put an expensive opti unit in there just to find it didn't solve the problem.

The opti itself will several hundred dollars depending where he gets it from. 260.00 will be for just the labor most likely. It almost sounds like he is guessing his way around the problem, I hope that he doesn't put an expensive opti unit in there just to find it didn't solve the problem.

You and me both.:D It still has a slight stumble in idle.He's been working on my car for along time and he's not been wrong with the other problems when it comes to my car. The $260.00 is including the opti including labor. The part costs around 250.00 on it's own,but he can get it for 185.00(new,ac delco).So he's only charging about $75.00 in labor. He does this for the people he has known for awhile.He builds and races his own dragsters in his off time,so I trust him that this is my problem.BTW,sound like you may have another opinion as to what it may be?

Well,
Got my car back today and more problems came apparent.The opti was bad and so was the water pump(they looked bad).The water pump was leaking onto the opti. He also noticed that there was a smell of antifreeze coming out the exhaust and white smoke which happens when a head gasket is bad.I have been smelling this for a week also. I stll get the random misfire,but he tells me that the leaking gasket is causing this.:( He also found out that my car had bad air lock and that may have contributed to my problem.I had another mechanic check the hoses and thermostat a month ago and apparently he didn't know what he's doing. I won't be taking my car to that guy again.:mad: Anyway,it will be a week before he can fix the gaskets and maybe,just maybe everything will be ok. :)