Cadillac Repair: Caddilac trouble code f85, throttle plate, throttle body

Question
QUESTION: 1991 Sedan Deville, 4.9 port injection
Car runs great until outside temp reaches 92 deg. or above. the car will start to cut out under load (take off or hill. if i pull over the car will idle fine rev the engine to a steady high rpm and it will cut out. i had a code e44 (o2 sensor rich)so i replaced o2 sensor with no effect. the other code received was f85 (Throttle body service required). I have checked all connectors and hoses attached to the throttle body. all ok. looking inside throttle body there ar two tubes under the flaps one is totaly restricted with a black buildup and the other partly blocked. Not sure what these tubes do and if that could cause engine to cut out when hot and under load. any ideas?

ANSWER: You found your problem which is this black residue which when hot turns to a jelly substance and blocks the idle air passage. You need to clean all that residue from the throttle body and do not forget to spray the small hole in the side of the throttle body just behind the throttle plate.

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QUESTION: Thanks, Thought that might be the problem. Should I remove the throttle body for cleaning or try to do it with throttle body installed? I can clean the tubes with it installed but not sure if crud will get into somewhere it shouldn't. Again thanks for the help.

Answer
You can try and clean it ON the engine. However there IS a procedure to clean it OFF the engine.

You will need the cleaning procedure and will have to check all the adjustments after you re-install it. You will need several pictures and this website only allows ONE picture. I do not have a website so you will have to e-mail: onlineautohelp@msn.com in order to obtain the information.