misfire at wot/misfire at idle follows

[GSX JOE]

Well my car was running great the other night on c16, had a couple of good races but at the end of the night my car would have a bad misfire at wot. At first it was every couple of pulls it would do it, then it became any time I went wot. So this became progressively worse and after I would get on it the idle would suffer and even just cruising speeds the car would miss and try to stall.

I changed my plugs and the car is still missing badly. So I was looking for anything obvious and decided I would unplug the fuel pump in the hatch and clear the pressure out of the lines, sure enough right after this the car started up and ran fine again. So I drove it around and it ran fine, put some 91 back in the car hoping maybe the c16 was bad and I got lucky but the problem persists on pump gas also. Its pretty wierd because the car runs fine unless I get on it and then it will misfire badly at wot followed by missing at any speed/rpm and it will die at idle. If I drive the car long enough maybe a min. or two the car will smooth out and run fine again (unless I get on it).

Well anyways its a wierd problem since it kinda comes and goes and is brought on by running the car hard so I dont know what to think, hopefully someone has some ideas. In case anyone is curious about the mods the car is a 92 gsx w/ 2g mas, 660's, 190 fuel pump, ngk plugs/wires, 16g, keydiver chip, fmic etc, thanks in advance!

 

[realhp=turbo]

Try replacing the fuel filter first
mike

 

[EagleTalonRacer]

run a compression test buddy

 

[GSX JOE]

Yea I havent changed the fuel filter yet but I havent heard of any filters causing these kind of problems but you never know. And I havent done a compression test in a while, but It has been below the serviceable limit for a while now, although it has still ran fine for quite some time. I Know I do need a rebuild but if the motor was that bad wouldnt It run like crap consistantly?

 

[EagleTalonRacer]

hmm, try cleaning the throttle body and intake manifold, crap starts to build up there after a while

 

[thebird_19]

I agree with changing the fuel filter. It is a cheap easy fix if so. Have you put any heet or anything in to see if maybe the fuel was bad? I had water in my fuel recently and my car idled funny and would die. I started looking at all the hard stuff and then my dad told me to put some heet in. My car started running fine after that. I have also heard of water getting in the fuel filter and moving around and when it blocks off the hole it'll stall. Just an thought.

 

[oldman]

I suspect you've developed a boost leak causing you to run rich under wot.

 

[GSX JOE]

Thanks guys for the suggestions. Im gonna run a boost leak test soon and I have the fuel filter sitting here I just havent gotten around to replacing it. I guess those are good places to start

 

[GSX JOE]

Well incase anyone cares I finally fixed my dsm. And what a stupid problem, im mad at myself for not realizing this sooner. I was messing with the car yesterday since it has gotten so bad the car cant be driven over 2500rpms and 6% throttle via the safc and for the heck of it I unplugged my 2g mas and guess what happened? Absolutely nothing! It ran the same .
So I pulled off the intake pipe and sure enough the large main honeycomb completely dislodged it self and was hanging on for dear life on that little upright bar (hard to explain) inside the mas. Im very lucky it didnt get sucked into the turbo! Anyways I bought the 2g mas off a member on this board, im not sure if he ever had removed it before but I have never seen this happen. I just feel really stupid that it took me this long to figure it out, ah well at least it runs again

 

[pickens]

Dude! my car had the same problem after running VP110! Thought it was bad gas, so I changed/cleaned everything fuel related and still have the problem from time to time. I'm gonna go check my MAF right now! Weird how the same problem and symtoms occur on two different cars.

 

[GSX JOE]

Cool good luck man, hopefully that is the problem! Dam dsms its always something

 

[pickens]

Unfortunately, my honeycombs were all in place. So that wasn't the problem. Hmmm...I wander what else little thin git could be.

 

[miliman13]

to those who are still searching for another answer . i just swaped out my green lid cam angle sencor to another of the same and it has been good so far i hope this can help some one else. 7bolt long block with green lid cas inverted signal with dsm link