Marko,

Don't know if this will help but it may be a dirty injector or so.

Maybe it's worth it to try an injector flush.

Good luck dude.

 

ok so i bought a new rotor and a new cap and its still doing it?

 

air filter
fuel filter
map sensor
temp sensor

can you force the problem to happen, or is it completely random?

 

^random. anyone know if an exhaust leak would cause it?

 

A dead o2 sensor would also cause those symptoms.

 

you say it sounds like a wrx with an exhaust.......burnt exhaust valve


or you switch the connections for the tps and map sensor

 

^ if it didn't only happen sometimes i'd think it was a bad valve too, but it's not constant.

 

today it has not done it, im not sure what the hell is going on, its been ok all day long, i left Jays last night and it was doing it, i get to the high way and get up to speed"slowly" and then all of a sudden it felt like someone was holding the car back and then let go, after 80 it was fine the whole way home nothing, and agian today nothin? i have no clue

 

could it be wiring related? I had a similiar problem with mine, turned out to be a bad connection between some of my ecu wires.

ps: does the check engine light come on when this happens?

 

no i get nothing, no warning or anyhting it just does it sometimes and then goes away like it was never there? I was talking with the Prez eariler and he seem to think its could be a sticky valve? dont know but its better than a burnt one

 

I believe if the exhaust leak is before the O2 sensor, outside oxygen is drawn into the exhaust. The O2 would read a lean air-fuel mixture and the computer will cause the fuel system to deliver a richer air-fuel mixture.
If the O2 was totally inoperable, I believe the system would remain in open-loop and use a set value from the computer for the amount of fuel to be supplied.

Personally, I wouldn't suspect the O2 sensor being a problem here.
To me, it doesn't sound like anything to do with the valves.
Looks like a misfire, probably electrically related. Maybe fuel related (i.e fuel filter, maybe a pressure regulator?
Injector problem?
Spark Timing?
Loose connectors/grounds?
Extrememly dirty throttle plate
Spark plug that is not gapped properly
Map sensor - might be giving the ECU wrong information. With the engine running, if the engine runs okay when disconnecting the map sensor, the map sensor is skewed or is giving wrong information to the ECU.

You got quite the head scratcher here because it seems as a random occurance.
I'm just shootin' possibilities for you.
Keep us updated!

 

thanks for the input i will, as soon as i get any info ill post it up

 

well we looked it over, i checked out asmuch as i could. i checked:

rotor - new
cap - good
wires - good
spark plugs - new with proper gap
checked for spark, firing in all 4 properley

so then i went under the car to check for exhaust leaks, exhaust is solid as a rock, i looked it over from header back, no cracks, no holes everything seemed pretty tight.

then i went to fuel:

fuel pump: should be good cause it primes just fine.
fuel filter: was working fine before swap
then i went to injectors:

- i pull out the injectors, the injectors were pretty grimey. they had black ---- on them, and one injector was cracked. so i had a set of JDM GSR injectors laying around, we grabbed those and i compared them and the silver part where the fuel sprays out of was alot cleaner than the ones in the motor. we slapped those bad boys in, but then the car diden't want to start, after checking for fuel and spark again which the car had, we tried it again, and it started, however was still running like poo.

then when marko went home, he hit the highway and then the car started working fine, and hasen't been giving trouble since.

so is it a dirty fuel injector? or could it still be a burnt exhaust valve?

 

Nice. Ok this is getting really interesting now

A dirty fuel injector will show a different resistance when checking resistances of all the injectors. The maximum differences between the injectors should be 0.3 to 0.4ohm.
Resistance checks of the injectors should be measure twice. Once when the engine (and injectors) are cold, and once after the engine has warmed up and reached normal operating temperature. If any injector measure close to over 1ohm different from the others, replace it. Also make sure that the connector terminals are clean and not green. Any corrosion on the injector terminals and even on the connector terminals could cause a misoperation.
Also, drag caused by dirt in the pintle bore (where it sprays) would cause a problem. What most of you might not know is that excessive fuel pressure can cause an injector to shut off. So be sure you are checking fuel pressure.
If you have a fuel pressure gauge, connect it to the schrader valve on the fuel rail
Turn the ignition key key on or start the engine to build up the fuel pump pressure. It should be about 35 to 45psi.
Wait 20 minutes and monitor the fuel pressure retained in the fuel rail. The pressure should not drop more than 20 psi in 20 minutes. If there is a drop more than 20psi you might have a problem with either the check valve in the fuel pump, a leaking injector, or a defective or leaking fuel pressure regulator.

Check the valves by doing a compression test. If u find a problem, then do a leakdown test. It'll tell you whether its your rings, intake valve, or exhaust valve. But it if were a burnt exhaust valve, wouldn't the problem be consistent?

Again, i'm just expanding/replying to what fuzzy's asking.

 

i think that was the problem, because the JDM GSR injectors that i put in looked alot cleaner in the pintle bore where the injectors that were in the motor had black crap in and around there.

 

So does he have the JDM GSR injectors in the vehicle now? And is the problem still there?

 

a burnt valve would make it run rought all the time. a sticky one might come unstuck and get stuck again.

it very well could be the injectors and they just need a good kick.

 

ok so today is the seconda day that this has not happened, but im skeptical because i drove it for a little while before this started the funny thing ios i havent put any milage on this newer motor so i dont know if its gonna come back, but i guess a compresion test is next thanks everyone for the help and if you have any other ideas be sure to post em up thenks so much again, oh and i like that word PINTLE BORE

 

Haha you like that don't you!

 

^well the car has the JDM GSR injectors in it now, and it's also running right now, so my guess is that it's the injectors were the problem, unless this happends again, then it could be the valves.