ok...

so driving today coming to a slow stop downshift...and revs hit maybe 4k give or take and the car stumbles.

Next thing you know it sounds like a wrx. At first it wasn't making boost and then it sort of "cleared it's throat" and started hitting 10-15 pounds but didnt seem to pull quite as hard.

No CEL's no rough idle...no burning smells or oil scattered everywhere....and the car is stock with just a muffler delete. Can't get to the dealer 'till monday so I'm a little on the concerned side and was wondering wtf is up with my car.

I even called GM and had them run the onstar diagnostics and NOTHING came up. So if the cylinders were fubared I'd imagine the car will still throw codes or go into safe mode or something.

Just wondering what I'm in for. Any ideas?

 

Based on my experience on this board, I've learned that WRX sound is NOT good. Best of luck to ya.

 

number 4...????

 

A WRX sounds like a lawn mower with a bad muffler. This has to be the 3rd post about this.

 

u had a misfire, a small one that doesnt register as a thrown code, i had one yesterday like that. Ur engine light probably flashed for a second like mine did, almost missed it.

 

The only problem is it STILL sounds like a WRX. It idles smooth runs; pulls relatively steady...etc but it's blatantly obvious that something is wrong. If it was just a misfire the car would be fine by now I would think.

If this is a blown motor or the cylinder is fubared...it's sure doing a great job of pulling 30 mpg on the highway and holding 70 mph without throwing codes. (I drove it home and parked it my driveway after this event)

!!?!

I've seen posts regarding the LSJ...that had people experiencing CEL's and oil messes ; the car shut down; limp mode etc...but I have yet to see a post where the car had no physical evidence of a problem and only SOUNDS like a WRX with an occasional stumble. It's still driveable (not that I'm trying that other than to get it to the dealer tomorrow..) and I smell nothing coming out of the exhaust etc....

I could not find this issue spoken about for a T/C.

 

pull the plugs and unplug the battery for a few mins and go from there

 

bring it in for warranty since u basically have no mods

 

broken flex section on your downpipe?? seems odd to me that you would have one already, but if the car is running mostly fine but happens to sound like its on its death bed, perhaps you blew it out. could be one of your cat's melted, clogged, ect, and the backpressure blew out the flexpipe. I guess that would explain the car hesitation too. just my .02 good luck figuring it out

 

Cats would be my guess too. I had mine blow out in my lsj twice... they just dont seem to like boost. But anyways the first time it started rattling a little made a pop and the exhaust got really quiet, power was lost but no boost issues. The second time it blew flames and sparks of molten cat into the road followed by a trail of smoke... the car died and a cop pulled up behind me that was following me and a srt for like 5 miles of us racing and messin around. But after like 20mins of cool time the car started up, still boosted, but was quieter, and lost alot of power. The cat had melted and blown in half. half going out and the other wedged itsself sideways in the exhaust.

 

I have seen LSJ's shoot molten bits from melted cats before kinda cool to watch.

 

Uh oh, J/k if it ran fine afterwords it may be o2 sensor or plugs. Just a thought.

 

Yea im sure it did look bad ass lol but it wasnt that cool seeing the red and blue lights flashing behind me through the smoke....... lol

 

Bad MAP sensor?? I had one go bad after a NLS. Runs much better now.

 

soooounds like an exhaust leak. possibly. My car actually got so loud that it sounded like a race car lol. I let the hole get biiiig lol

 

mine did the same thing i got a catless dp mine runs fine no leaks or cels so idunno im not owrrying about it

 

Mine all of a sudden started doing this at around 13,000 miles. Its kinds scary still to hear it, just waiting for the big pop!! but ive got 16,000 on it now and ive tracked it a few times and its absolutely fine. ONly thing i did was overboost the map sensor this past sunday and now i have to replace that. but i still want to know why its wrx-ish??

 

To the OP: Did you make any recent mods or go on a long trip or something? It may be fuel trims causing a misfire.

Try resetting the ECU by unplugging/replugging the ECU or battery and see if this fixes it. It will reset the fuel trims and fix the problem if that's a part of the issue.

Mine's had a misfire issue after a long trip at steady RPM/speed. It would cruise fine, but I couldn't really get into boost without it stumbling and puttering out. Driving around the city again helped it. I found out later resetting the ECU fixes it too.

 

wrx sound means something is wrong with the inside of the engine. plain and simple.

 

I remember them figuring out what the WRX sound meant a while back (search for threads on it), but I was hoping he'd at least be able to knock a few possiblities off the list. It's not hard to unplug an ECU/battery. Better that then start needlessly digging through an engine.

 

I've unplugged the battery waited 20 minutes...and still have the same result. Took the car to the dealer...and they said that there were no codes and therefore nothing was wrong. (Even though the car was off the reservation in terms of sound and gas mileage.)

Paid for a compression check yesterday...and the damn thing is even across all cylinders...so thank god it's not a blown cylinder. Spark Plugs look good as well and are tightened down.

Throwing it on a lift today to try to see if it's the cat...

I mean hell it HAS to be the cat...no codes...compressions fine...etc...


Most frustrating troubleshoot I've ever had with a vehicle. lol

 

wow I'm curious as to the outcome.

 

gotta love it when the dealer can hear/see a problem but says since it didn't throw a code that nothing is wrong.. great technicians there.. idiots.

 

I had the WRX sound on my LSJ for a long time and nothing was wrong. Swapped out the downpipe and went catless and no more WRX sound.

 

So spark plugs are fine, cats are fine, no codes, no exhaust leaks....

but the mileage sucks and it sounds like a WRX...

I have no $*#@ing idea what is going on here...

GAHHH!!!


I swear to god there is nothing left to check...