Questions and problems.... help me out guys! (LOONG)

[Datsunboy]

Guys, my GN is being a b@#ch. Help me out here. The car is idlng like CRAP. It feels like the thing has a huge cam and lumps, the problem is it does it at all RPMS if you hold the throttle steady. The motor is surging. Its also not making as much boost as it used too. The boost gauge wont go all the way up (like it did when i first got it). And if the car idles for along time the throttle reponse goes down the crapper, and the motor does NOT want to spoolup or make boost. There is a "miss" in the throttle when you step on it off idle sometimes.

The weather is cold here 30s or so. Its also humid. The car has been exibiting these oddities since I got it pretty much.

I already did wires and a O2 sensor. It ran bettery with the new 02 and now runs crappy again. Did i fubar my O2 when i used marvel mystery oil in the gas? Could be. I need to check that its still tight too come to think of it.

It also sounds like i MAY have an exhaust manifold leak on the drivers side. Is this at all common?

Does anyone elses intake system make a ROAR when idling? sounds really weak and id like to quiet it down. I have some random cone filter on there. K&N clone i do belive.

I am questioning my cat converter as well.

Sorry for the long post guys. bear with me here!

Thanks - Evan

 

[FJM568]

First question...

Why Marvel Mystery oil in the gas???

I'll let you answer that one, then we'll go from there...

 

[cool 84]

How much mystery oil? It lowers octane and you could've hurt a headgasket. Also, the intake sound you're describing could be the IAC all the way open (it's pretty loud with an open K&N) or a big vacuum leak.

 

[FJM568]

If you put in any more in than the little cap on the top of the Marvel Mystery oil can in full tank of gas, it's too much...I have heard people putting it in when they run xylene as octane booster, but I never have...If you put more than that in, I would drain the tank, change the fuel filter and put fresh gas in, clean the plugs and see how it runs...

 

[Datsunboy]

I have had good luck with marvel oil in fuel to help clean out nasty poorly maintained motors (my motor). I used the specified quantity per gallon when i did a fillup.

I have not heard ANY detonation from my motor when driving, and am already on a fresh tank of fuel.

I may do another tank of fuel after this one and do Another o2 just in case.

The loud sucking sound is coming from the air filter for sure. I guess the loud intake comes with the territory. Just wanted to make sure that was alright.

Thanks - Evan

PS.. I have a new fuel filter right here that i want to install tomorrow along with a new set of plugs. Please confirm for me what the delco number is for the plugs for a stock GN?