iPhone black screen

[Joker1535]

Every time I make or receive a call the screen goes black and it takes about 10 seconds after the call to come back and I'm able to press any buttons. It's not the sensor but it happens after downloading a tweak or app I guess.
Anyone ever had this and an idea which one screwed up my phone?

[Simon]

If this is an iPhone 4 it may be your proximity sensor.

[Joker1535]

It's a iPhone 3GS.

[Simon]

Might be something you installed then, you may just need to do a fresh restore.

[Txedman]

Do you have a case on your phone? My wife's phone did that - ended up being the case covering the sensor.

[jrichards2007]

If you have SBSettings, I would go into the More Options for that, and disable MobileSubstrate addons with that one by one until you found what was doing it, then you can uninstall it.