Volvo 850 T5 (2.0) Impossible (for me) to diagnose
 

Hi there!

New member here, although I've read through lots of posts.

My 850 T5 is having some sort of an issue, where under load it reaches like 4k rpms and then seems like fuel is not enough, running like on 4 cylinders and with probably 30% less power.

So far I've changed the MAF, Spark plugs, coils, air filter, tested the FPR and the fuel pump relay, checked the TC valve routings, checked vacuum tree..and nothing. I have some codes, but i've had never checked them before, so i don't know how recent they are.
121-Manifold absolute pressure
232-Lambda adjustment
533 - Power stage group C
535 - TC valve
231-Lambda adjustment, heated oxygen sensor (mixture too lean under part throttle)
/ long term fuel mixture too rich in part load stage

Also i should mention that i see a crack on my throttle body hose and a Lambda light is on.

I would really love for someone smarter than me to give his 2 cents. I'm leaning toward O2 sensor, but enough buying parts in the dark, so before I'm able to determine what exactly the issue is, i cannot afford buying anymore parts :(

Hope you guys understand,
Thanks in advance.

First, what year is your car? The codes you listed do not show on my list of Volvo port codes. Second, Clear the existing codes since you've never checked them and fix the crack (leak) on the throttle body. Take it for a long drive and check the codes again.

Hey there, it’s an 95 model and it has obd 1, so im doing the led diagnosis.

i will have to see how to clear codes

This is what I have for OBDI cars. If you need a TCV, a few of us are using this as a replacement - LINK

Hello again, few days passed by. I did couple of stuff with no success.

unplugged the battery, it did reset the codes. Car ran alright, with that missfire or cutting a cylinder after like 4k rpm back again. I have been driving it like that for a few days and it started getting bad again. Changed the throttle body, because of a crack, nothing.

starting to think that i might have a bad coil or rotor.