Okay Veeky Forums Need some help here. I own a saab 9-3 se with some questionable history...

Okay Veeky Forums Need some help here. I own a saab 9-3 se with some questionable history. its had some mods done to it to say the least. But unfortunately It's got a problem now that I just can't diagnose and google isn't helping me.

So the car runs amazing, unless I give it 100% throttle. then the car climbs into boost and then just shits the bed and starts sputtering and jerking. its not rythmatic. And it doesn't even happen all the time. Sometimes it'll go into boost and fucking fly. Here's the known problems and what I've replaced. SO I know the throwout bearing is going out but I dont think its related. and 2ndly, the previous owner put a custom 3inch downpipe on it and i had to unbolt it when I dropped the oil pan, but now I can't get it entirely bolted on and theres a small leak, however it's been there before this problem started happening. So again. I don't think its it.
Now the only check engine light I get happens randomly and usually when I'm on the highway under normal driving, its P0101. SO I replaced the maf and ended up getting misfire, retarded timing and limp home mode. So I swapped them back and returned the maf. The only next step I can do is replace the Direct injection casset but, they're pretty pricey and I have no idea if it'll fix it. What do you think Veeky Forums?

Test your 02 sensors pull them to see if they are fouled or not. Your engine runs off of it when youre going full throttle (open loop mode)

I should mention that leak where the downpipe bolts to the turbo is like a couple inches before the front O2 sensor.

in open loop mode, your PCM ignores the O2 sensors

you have a p0101 code which is related to mass airflow sensor - just because you replaced it and it ran worse doesnt mean the original one is good - you need live data from a scan tools to properly diagnose this. And why would you put anything related to direct injection on without a proper diagnosis - stop guessing and throwing parts at it and take it to someone that can diag the problem

you cant have a leak before the front o2 sensor - that will seriously throw off the pcm - fix that first! do you have some aftermarket pcm or tune? because that should set some codes

Again, with the questionable history, I don't know if it has a tune but I'm going to assume it does, because it's faster than a buddies stock 9-3.

Fix the leak

But i'll go ahead and fix that first before I do anything else.

I was going to replace the DIC because reading some fourms on similar problems, A dieing DIC can cause strange problems like this and not throw any codes

Summoning Snaab.

Dammit Veeky Forums I don't need that trip now.

Don't replace the DIC yet until you start getting miss codes or one of the "sooty spark plugs" codes (P1312/P1314). The leak seems to be your main issue here. The other thing I would check is if the recirc valve was replaced with a generic dump valve of some kind.

In fact, do you have a top-down photo of your engine bay? I want to see if I can perhaps glean something from that.

I don't but give me a couple of minutes and I can get one for ya. I'll take the 2.0 cover off for you aswell.

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For those who want to see the leak

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its such a small leak you can't even hear it. you wouldn't know it existed unless I told you.

Your efforts are appreciated, shit like this really helps.

Well, it looks like he kept something similar to the stock recirc valve, though it's entirely possible that there's an issue there. Recirc valve issues, however, don't really match your symptoms.

I'd start by doing the following:
1. Fix that exhaust leak, it's probably causing some other problems.
2. Check all your vacuum lines. You can find loads of schematics at various places especially if you go to Saab Central, Saab Link, or Saab World or one of those similar forums. Lots of how-tos on YouTube as well.
3. This is optional, but it's a good idea in general. Replace that recirc valve with an aftermarket metal one. Only reason I haven't done it yet is cost (they can run pretty pricey) but it's worth it for the benefits it provides, especially if you're running a downpipe.

It's also possible that the ECU was never properly reflashed to cope with the downpipe. This is harder to check on if you don't have easy access to someone with the applicable software, though.

fix that shit nigga

I've checked the vacuum lines and replaced them, I actually got rid of the vacuum lines from the 3 way valve on the top right next to the firewall, and put the recirc valve hose directly to the throttle body, since I was told this was okay and those hoses where ALWAYS popping off. It helped throttle response so much it's night and day.

Welp, I guess I know what I'm doing this afternoon. Just figured this wasn't the main problem since it never did it in the past.

Sounds a tad suspect to me, but as long as that air circuit's completed it should be okay. I've got to double check the routing, though, I'm not as familiar with the 9-3's version of the vac routing.

But yeah, as of right now, best thing to do is get on that leak.

This is actually exactly what I did. yellow and red lines are supposed to be taken out, I actually did this to try and fix the problem but realized its so much better because I'm also not blowing off those hoses every time I hit boost in 2nd.

but why.