Just recently got a Evo 9 fully modified
But on cold start it starts up real lean at 21 afr and when starting in to first gear it is very boggy. Hits boost fine runs fine after you get going. Cruising in 5th and going to open the throttle it bogs and you have to down shift into 4th for it to go away. When that happens the afr reads 21
Please help could it be a Map sensor issue or a tune issue?

 

It could be many things. Who tuned it? Is it tuned for speed density or MAF? What parts are on the car?

 

Engine:
2.4L Bottom End
Curt Brown Ported head
10.5:1 compression wiseco pistons
GSC S3 cams/Beehive springs/Retainers
Kiggly HLA
AMS head gasket
FIC 2150 Injectors
Buschur Double fuel pump
Upgraded oil cooler (STM)
10,000 miles on motor


Transmission:
Shepbuilt Ultimate ratio (Evo VIII 1st, Evo IX 2nd, 3rd, 4th, Evo VIII 5th)
Quartermaster 8leg[Street flywheel] w/ hydraulic throwout bearing
12 plate rear differential upgrade
10,000 miles on transmission

Turbo/Exhaust:
JesseB front facing T4 turbo kit
PTE 6266 1.0 AR (350 miles)
Tial BOV
Turbosmart Wastegates
JesseB Downpipe
Custom JesseB front mount (using a Garrett 3.8 core)
Customer IC pipe
Evolved Components custom AC kit
Evolved Components Battery relocation
Spec-Ops custom Titanium dump tubes (routed out of hood vent)
Tomei Titanium TestPipe
Tomei Titanium exPreme Exhaust
Tuned by Spec ops motorsports which is now out of buisness
Unsure of what it is tuned for

 

Good bet it's on speed density. Do a boost leak test, then go see a competent tuner..

 

You running E85? Don't keep getting on it until you figure things out because if the car is running that lean in boost that's a lethal combination for your motor. Any idea what AFRs are when it's idling smooth or in full boost and appears to be running well? Running E85 on a 93 tune would cause you to run really lean is why I thought to mention that.

Don't get on it from a low RPM in 5th by the way. You should be at a point where you're going to be really building boost before getting on it in 5th.

 

Check your fuel pump as well, when I upgraded to a new fuel pump somehow we forgot to transfer over this little white plastic piece that sets just below two o rings on the fuel pump itself. Anyway caused all kinds of issues and took awhile to figure out what the hell it was going on. I can put up a picture to what im talking about as well if you need it.