I have an 03 forced induction Z throwing a multiple missfire code. I changed the plugs, and it is still growing the code. I am also running rich. My mpg is at 13. Help, please.

 

more info, mods, tune, etc.

did you get get your car? there aren't many of us boosted in indiana.

 

Modified boosted it August 2009. 550 cc injecters, GReddy twin turbo, upgraded walsboro fuel pump, HKS FCon piggyback computer... HKS boost cintroller.

 

I got this code last time I changed a knock sensor and spark plugs... It as no link with these and actually it was the intake manifold that cracked when I loosened the nut.

It was running rich as sh*t and was idling pretty rough...

Hope it can help you out!

 

rich from an intake manifold crack? that would suck air and cause a lean condition. interesting.

OP: since you have an fcon you're going to have to contact a tuner to adjust your box. It's locked for end users.

The misfire is probably do to the rich condition although 13mpg sounds about normal for a boosted car if someone frequently gets on it. hell, OEM city mileage is only in the high teens anyways. Add boosted city mileage and 13 is probably about right.

If it IS running rich that would flood the plugs and cause a misfire. when you took the old plugs out did you look at them to see if one of them wasn't firing? I always take them out, mark the cylinder numbers on them and make sure to hang on to them to check.

 

The two plugs in the driver side had some oil on them. The person who tuned it, the shop is closed here in Indy... I might be sol?!? Dang!

 

that might just mean you have the common valve cover leak

 

Tighten down the valve cover? Never thought if that. Is it a certain torque setting so I don't crack it?

 

My MPG is 3 help....

 

I drove it last night, and sometimes the service light blinks when I drive.... And when I'm idleing it doesn't blink... why?

 

you just put new seals in it....

 

It blinks because you have misfires. If it blinks that means it's bad. When it flashes that is a "stop doing what you're doing light"

You could have a million things wrong, spark blowout, bad coil pack, bad wire connection somewhere, too rich flooding the plugs. Those would all cause a misfire.

take it to dreyer and reinbold and have them look at it. There isn't an fcon tuner in a long way so you're kind of screwed on having someone adjust the EMS to lean it out again.

 

Take it to someone who knows what the hell they are doing and open your check book.

 

Did you say there's oil on two of the plugs? If this is oil on the firing side that's not so good. How often do you have to put oil in it? Also did you recently change something, either on or off the car? When you get a chance try a compression check, I'm thinking the oily cylinders will be fairly low, if there's oil in the combustion chamber.

Also a quick test to find out which cylinders are the problem is to load/power balance the car. This is done by removing the coil leads one at a time to see which one causes the engine RPM to drop at idle (After you remove the lead to test put it back on the coil before moving to the next). The leads that cause a noticable drop, ideally are working well those that barely drop are probably the problem.

 

Jeff if there is oil on the plug, he will need a new valve cover the seal around the spark plug tube is not replaceable. If it was leaking out of the valve cover he could replace the valve cover seal.

What codes is it throwing? p0300?

 

Solid means get it to the shop ASAP. Blinking means stop driving it ASAP.

 

It flashed back in March, then stopped, then flashed again June and stopped... Then again recently... Won't hit boost. I took it to a shop today, just don't want to be taken advantage of...

 

won't hit boost meaning you floor it and boost doesn't build? that means something is really f'ed.


also, i'm going to say it's not oil on the firing side of the plug. Everyone that says "my plugs have oil on them" mean when they take the plug wires out and there is oil down in there. Except if they are a mechanic, then they know the difference.

 

Just went through a bunch of this stuff my self. Then car would idle fine but die when I gave it gas. Finally tracked it down to a faulty maf sensor. Problem solved. This was on a boosted 03 G35.

 

The car just needs to be looked at. You potential have a dozen possibilities as to what is wrong. Give us a call on Monday if you need any help.