Here's the situation.. My 03' type s(120k) has had a misfire problem for some time.. I gave up but recently had to smog it.. It passed but my CEL still comes on.. so the codes are p300-306 and p1399.. so bascially every cyl. misfires plus a random misfire code.. So far i've done a valve adjustment, changed plugs, changed my egr valve(it was bad), changed imrc(i think that's what it's called but it's that butterfly looking thing toward the back of the engine), tested coilpacks, ran compression test(good) leakdown test(2 cylinders at 12% and the rest @ 5%) ran a dyno before changing egr & imrc and it was running rich(so that would rule out bad injector's, right?).. the wierd thing is my CEL is usually on, almost always my VSA light's would come on also after a couple of minutes of starting the car.. The car dosen't seem affected ie it runs pretty smooth but i did notice even though the rpms idle at 500 you could hear the exhaust tone change from high to low..My mods are exhaust,Headers(DC),CAI(injen) & TB spacer.. I fugure if it's some kind of sensor it would throw a specific code for that sensor(02,crank sensor,knock sensor).. If 6 cylinders were really misfiring I think the car would run pretty crappy( I disconnected 1 coil and the engine was shaking)..i'm all out of answers and don't want to spend money on guessing..I will post some video's on how the car runs/idles.. even if i disconnect the battery, the cel would come on in a day or so..Help!

 

You said you tested the coils but have you tried replacing one and working the new one around the motor to see if it solves it. The coil may test fine but once under load one may be faulty. Our cars usually throw the multiple or all when its just one coil.

 

^ i agree.. i wouldnt rule out coils just because they tested good. but also it could be a bad injector too. does the car start up rough and then get better when its warmed up?

 

Starts up fine no stalling or dosen't cut off.. I had someone test the coils under load.. also myself I disconnected one coil at a time and each time I did it the car sounded rougher/misfiring.. wouldn't my performance suffer greatly with a bad injector?

 

not really because the injector(s) might not fully be clogged. now when you check the CEL what code comes up first? usually their not in cylinder order so start by checking out they cylinder that comes up first with a misfire. clear the light, switch the coils around and turn it on. if the same cylinder comes up again as a misfire id say its that injector going bad... has the car ever over heated? worst case it could be a blown head gasket.

 

I will try that... no blown head gasket like i said the car seems to run fine.. I also cleaned out the egr ports.. I will try to get video by tommorrow

 

Disconnecting one at a time to see if the ide remains the same ONLY works if one just doesnt work. There could be just 1 thats bad causing the misfire. A fuel injector not working optimally could cause it, a front O2 sensor could cause it and lastly a ECU problem could cause it. My guess it a coil or fuel injector. I would start out testing with 1 new coil and resetting the ECU every time.

 

I'm gonna buy a coil today. Do I start w/ the front/left coil? Also do o2 sensors throw a specific code? What are the signs of having a bad coil/02sensor/injectors? I also have an ecu from my friends 03 type s but thats my last option.

 

try starting with the cylinder that comes up first on your scanner as a misfire. there are specific codes for the o2 sensors (P0135)(P0141). signs for bad coils or injectors or even o2 sensors is misfire codes. swapping ecu's unfortunately wont work because the immobilizer is built into your ecu and it wont recognize your key.

 

^ Though seeing you have all 6 showing and not one or 2 i would start out with #1 cyl (passenger side rear) and work your way to #6 resetting the ECU between each one (yes a pain and time taking) and see if you can isolate if its just a coil
123
456
Front of car

 

So I bought a coilpack and will change cylinder 1.. The salesman swore on his name that it was the map sensor, I accidently took of the throttle position sensor(i'll take a pic to make sure) now my vsa lights won't go off(could this be the problem as everytime I'd drive the car my vsa's would come on and stay on even if my cel was on, also if i reset the codes, the cel would always come on with the vsa's, never just the cel...) He also stated I have a crank sensor and cam sensor that could be bad but i would think it would trigger a specific code..

 

yea i wouldnt listen to the salesperson.

 

So i replaced coil #1 and cleaned my CAI and now she REALLY feels like she's missing, CEL came on after a couple WOT's.. VSA's are stuck on I don't know what the hell i did wrong, whatever I pulled apart I put back exactly the same way..So maybe my throttle position sensor was bad the whole time??

 

wuts the CEL code?

 

p300-p306, p1399

 

put the new coil in cylinder #6 front head all the way to the right. if it comes up again as the same code once you switch it you'll know its the injector.

 

So did I screw something up by pulling apart the throttlebody sensor?

 

no those codes are for a misfire

 

Someone told me i need a multimeter to put the throttlebody back together

 

dont worry about the throttle body. theres no codes for it.

 

I kno but ever since I took it apart, both of my vsa lights won't go off

 

did you put it back together and then forget to plug in the tps sensor?

 

No, everything was put back together exactly as i found it..

 

ok so there shouldnt be any concerns with the throttle body area. just keep checking the CEL and make sure there arent any new codes. have you made any progress with switching the coil to #6?

 

This is what i'm not understanding.. Although the codes indicate misfiring on all cylinders, it runs good.. pretty good actually no gas milage problems power is there(my 08' recently had a misfire on 2 cylinders and she ran like shiet) Idle is good around 500rpm's it dosen't move around..I bought a coil and switched it around and it runs the same.. If it were any sensor it would throw a specific code.. So i think it's a faulty computer which I have one from my buddies totaled 03' type s and for $120 i could have it installed and programed to my car..

 

any updates....

 

I have the same problem with my cls6 done the injector n coil swaps. Still the same codes.

 

Dont remember the code, but the throttle position sensor is part of the throttle body. I had cel and vsa lights on because of a bad tps. Dealership ended up replacing the throttle body...

 

Totally forgot about this thread. So the problem was one bad injector. It wasnt functioning all of the time so I guess that's why It kept throwing the random misfire code. I also had a valve adjustment done.

 

Hi,
I had the exact same codes on my wife's 02 tl-s. shakey on decel.
tried the coils no go.
Valve adjustment, new plugs and we are back to smooth as silk.

hope this helps.

 

plugs are really important and the right ones!
over 70kmiles on them and its ready for new

valve adjust is supposed to happen at 105 but rarely does, when off spec a MM it effects the running

Since we need to clean out the egr system with intake manifold removed
thats the time for valves- already halfway there in parts removal!

a well adjusted engine gives better everything

now that its running better:
a can of seafoam in half a tank of gas- do that twice and its clean from filter sock to injectors, intake valves, fuel rails, pistons, cat and even O2 sensor all benefit!
real tune up in a can -

important to clean carbon from our engine, type S has even higher compression and really needs to be kept clean