Hey guys, I've posted before about an issue I had with my sc400. Basically it would start misfiring as it got warm, then gradually build up until it was stumbling, hesitating, etc... After a while it started running horribly right at startup.

Also when it wasn't running right I could stomp the pedal and it would stumble, and move slowly, but once it hit 3,000rpms the car would launch and pick up speed.

I did the whole tune up deal, plugs, wires, caps, rotors, coils, etc.
A couple times the problem would go away, only to return a couple weeks later.

I hadn't driven the car in a while and finally decided to take it to a shop yesterday. They said what I already knew, it had good spark, compression, etc. Their diagnosis was that injectors 1, 2, and 7 were getting spark, but not function properly (dirty or stuck open/closed, etc).

So today I go to start it to take another look, and suddenly it idles and revs up fine again. However it did seem to burn off a lot of raw fuel at first.


My question is what are the chances that these injectors would all of a sudden "unstick" at the same time. Could the problem actually be a faulty ECU that is randomly causing them to either stay closed or open?

 

i am kinda having the same prob but mine dose not go away. and i did the tune up as well but still falling on its face. mine is a sc300 but i am thinking vac leak

 

bump........

 

Well I have an ECU and injectors coming, so I guess I'll figure this out soon enough.

 

please tell what you come up with.

 

will do...

 

Got the ECU today, but it didn't fix the problem :/.

The car is running very rich, burning fuel out the exhaust.

 

Well you can get a scanner adaptor thing and I think you can get some software online where you can monitor what the ecu see's sensor readings and etc.... Might help you diagnose the prob...

 

i am thinking fuel filter. of couse noone around here has them so i have to order and it is 2 weeks out.

 

I'd replace the fuel filter since its cheap and probably needs to be done anyhow. Also, check the fuel pump and make sure it's functioning properly.

I would try running some "good" fuel system cleaner through it as well. That stuff can work wonders.

 

let the car run rich for a couple of days on that ecu....it will get better the more u drive it...i had similar problems with my 300 and after i change the ecu couple days later it was back to normal..

 

he tried that.

 

man these sc's are always coming up with mystery problems---good luck and please keep us posted

sorry i really have no advice to offer you--it would be purely guess work

 

I ran some injector cleaner through it yesterday, it still hestitates and lacks full power, but seems to rev out a bit smoother. The worst spot seems to be 1500 rpm, hold it there and you can make the car buck. But if I accelerate faster and it actually has semi-decent throttle reponse 3000 rpms +.. maybe its getting too much fuel and at higher rpms is able to actually use more of it?

The weird thing is when the car is at its worst a few cylinders go completely dead, you can pull the plug wire and has no affect on the idle. But like now when it's just moderately hesitating pulling the wires does affect the idle.


Oh I forgot to mention the CE light has stayed on now. When i took it to the shop they said it was caused by the O2 sensor, most likely because the fuel mixture is off. I may borrow a code reader from autozone this weekend to see if any other codes come up.

 

u can check the codes by running a wire from terminals----te1 and e1