Ok, I have not been on here for a while. I am at work so I don't have a lot of time to use the search. Lately my car has been hesitating when I hit boost for like a second, then it goes like it used to. I also have had it " pop " a couple of times when I am between 5500 and 7000 rpm. I have my stage 2 tune in right now, tryed changing the plugs. I have really started to notice these problems in the last couple of months since I had my Gmpp Sport exhaust put on. Does anyone have any Ideas as to what might be causing this??? And no it is not the 2.8 pulley, it has been on for like 30k miles now. This all really started after the exhaust install

 

hmm, this seems to be happening with a lot of the LSJ's. i believe it is your map sensor. PM 04redline0124. he was a local to me who had the problem for quite some time. he can tell you in more detail than i can about the problem

 

Hmmm, I have not thought of that yet. But I should add that I have not had a CEL come on yet. I almost wish it would so I have a starting point

 

Possible boost leak? Keep an eye on your boost gauge when accelerating.

A friend of mine had something similar happening to his car. We fixed it by installing new NGK BKR6EIX spark plugs, cleaning his MAF sensor, throttle body, and air filter. Since you've changed your plugs already, that may not be the problem. However, I'd check into the MAF and MAP sensors. Hope this helps.

 

I also have a new MAF sensor and K&N filter, I had to replace both when my intake f'ed everything up. Where should I look for a boost leak? Also where is the MAP sensor on the LSJ? Thank you for the help

 

Have you removed your supercharger recently? If so, the four bolts that hold it down could possibly be loose. If you haven't removed your SC, check them anyways. Next, find the three vaccuum lines. One is small and comes from the SC to the by-pass valve. The next exits the by-pass valve and runs to one of the MAP sensors. The last runs from the back of the MAP sensor and back around under the fuel rail and into the intake manifold. They are small 3/8 rubber hoses. Check them for dry rot or any broken areas.

There is a MAP sensor that ties into those vaccuum lines, and there's a MAP sensor that is located on the passenger side/top of the intake manifold.

If your MAF sensor is new then I wouldn't worry to much about it. However some are known to be defective. I'm sure it would throw a code if it was defective. Other than that, I dunno how else a boost leak could be made.

EDIT:
I just realized something. You say your intake messed everything up? Did you have to replace your MAF sensor because your intake sucked up some water? If so, then you may have a small rust problem. The by-pass valve controls a little flap on the inside of the supercharger. That little flap, or blade, is connected to a shaft that has two small bearings on each end. If you sucked up some water, those small bearings may be rusting.

 

My car did the same thing when i was testing SP gaps recently. I opened it up to .43 and the thing fell on its face when i would mash the throttle . It spit a popped like it was starving for fuel ( spark blowout) . I regapped the brk7e's to .33 and problem disappeared completely . I know it sounds far fetched but thats how it worked out. Haven't had a issue since.

 

I need to check that, you are right. I took my intake off because it sucked up water ( and slush because it was the winter) and replaced it with my stock intake and K&N drop in. The slush destroyed my MAF sensor. Now if the valve plate was rusting and getting stuck would the boost gauge go strait to 15-17 psi anyways? Even when it is lagging the gauge reads between 15-17 psi.


Anyone have any idea's on the backfiring? It does it occasionally at WOT between 5500 and 7200 rpms

 

just found this thread. I've been haveing similar problems. I put the hahn cat back on 2500 miles ago and this just started within the last few weeks.

I've been only driving to work and back since it happened. and last night on my way in it even stalled out on me. It wouldn't start back up for a few minutes. After that everything was normal. It started raining so i couldn't really get on it to see if the studder was still there. I'm goin to change the oil and plugs today and see whats up after that. going to check the threads for what plugs and gap i should use with stg2.
*bump*


Edit" * I just noticed something. I was thinking about this before. I had to re-use the origional exhaust gasket when i put my new cat back on. It was pretty beat up. I went on a call (paid call, Fire/Medic) and when i got back i decided to look under the car. I did notice a little exhaust leak and some built up carbon at the flang. I should be able to pick up a gasket anywhere. 2.5" right? when i replace it I'll let ya know what happens. *so check for exhaust leaks.

 

Running Great!