groundzer0

like the title says...throwing codes for random multiple misfire, cyl 1 and cyl 6 misfire. it will come on shortly after start up at idle, blinking and stay on and blink randomly (misfire). the car runs perfect. i got it a couple weeks ago, had egr code but prev owner replaced it and temp sensor but code was still there so i just deleted the egr and wired in a resistor... im trying to get this thing inspected so i can put a plate on it...helllllllpP!!!

StiCk3

iTrader: (5)

SC300 or 400? and when was the last time plugs were done?

groundzer0

Sorry i typed that in a rush. Its a 97 sc300. Just changed the plugs (ngk platinum) and wires, cap, coil. Cel still popping up. Crank sensor was all gunked up so i cleaned it off but has been soaked in oil for a while. No vac leaks. Deleted egr. Redid ignition timing to spec. Fuel trims are damn near perfect. Cat was melted and clogged so i gutted it. Ran a whole bottle of seafoam through an iv bottle and put another in the tank with 93 octane. Cel still on but runs/idles perfect. Cel didnt come on the other day with maf unplugged and idling....

2jznosht

You need to either buy a new maf, or swap a known good one in to rule out a maf problem

groundzer0

maf readings are good on my scanner. threw on a new crank sensor today...nothing changed, well...seemed to idle a little better but same codes. i saw earlier on a range rover forum about bad vss signals causing a random misfire code with specific cyl misfires. i know my vss is bad but havnt replaced it yet. has anybody else heard of this happening? it makes sense, the vss will send a speed limit signal and will cut fuel on certain cylinders for that split second and cause the misfire code with or without symptoms... looked at the freeze frame on the misfire and the fuel trim was like 25! so its a possibility.

sprafrk21

Did you ever figure it out? I have the same codes and it runs perfect, even according to a solus ultra... I have changed plugs, wires, cap, rotor, distributor, and coil.

Ali SC3

iTrader: (10)

how many miles and have you guys done the o2's.
the egr was probably a symptom of running lean, its just a exhaust temp sensor, so when you have misfires from being too lean, the exhaust gases increase alot and the ecu thinks something is wrong with the EGR, when in fact there is something wrong much further up stream. has to be a fuel or ignition issue, sounds like you have changed most of the ingition, so something like o2 or maf makes sense. on a 97 you have a hotwire maf which is easy to clean, and its good maintenance to do so every once in a while with the proper cleaner. odb1 92-95 you shouldn't really clean the maf sensor unless you are crazy carefull and the process is different.

sprafrk21

my issue is a little more sporadic. I haven't found a way to make it do it. Sometimes it will do it when Ive been driving for awhile and other times right when I start it up, sometimes the cel will constantly flash until I shut it down and other times flash only a few times.

It seems like a short somewhere but I have gone through the grounds and the connections and still nothing. lol it makes me want to buy a gte engine cause they're so much easier to mess with from my experience.

Ali SC3

iTrader: (10)

most likely on this would be o2 sensors if the car appears to be driving fine otherwise.

CunamaySC3

Don't mean to bring up an ancient thread... but I'm new and I gave a 97 sc300 I just got about 3 months ago. I'm having the same codes on p0300 p0301 and p0306.

They came on after I did my timing belt. I had a bad exhaust leak for a week or so at the header which I fixed prior hand. I have replaced spark plugs, wires, cap and rotor, re did timing belt, compression test showed 180-190 accross all cylinders, and even replaced injectors.

My scanner shows the freeze frame data at idle running lean In both banks ranging from 14-19% I imagine my 02 sensors are working because when I clear the code and it comes back the fuel trims are different but all within that range. I'm stuck and I know it's bad to run a car lean.

HELP!

groundzer0

[QUOTE=CunamaySC3;9299587]Don't mean to bring up an ancient thread... but I'm new and I gave a 97 sc300 I just got about 3 months ago. I'm having the same codes on p0300 p0301 and p0306.

They came on after I did my timing belt. I had a bad exhaust leak for a week or so at the header which I fixed prior hand. I have replaced spark plugs, wires, cap and rotor, re did timing belt, compression test showed 180-190 accross all cylinders, and even replaced injectors.

My scanner shows the freeze frame data at idle running lean In both banks ranging from 14-19% I imagine my 02 sensors are working because when I clear the code and it comes back the fuel trims are different but all within that range. I'm stuck and I know it's bad to run a car lean.

HELP![/QUOTE

Well I ended up putting a new timing belt pulley/reluctor wheel. The 97 has a cp sensor in the distributor as well as at the crank. I've read that people have had issues with the wheels breaking or coming loose off the pulley. It seemed to fix my codes but I also had other things wrong with it. I don't have the car anymore, a drunk driver hit and totalled it along with my crx racecar in front of my house a few months ago :/ . have a 92 sc400 now