wierd stuff...

OK, so like a good owner of a truck that has the original drive train with 172k miles - I try to let the old girl warm up in the morning - however carbon will come out in the exhaust. Before you all start LOLing at me and tell me that it's blow-by and I need to rip the engine half apart - it is a black powder when it dries, so that tells me that my truck is running rich. So here are the questions:

1. is there an idle adjustment screw? and where might that be?
2. Where is the "computer" thing located? I have also read that sometimes you need to clean that off to make sure it is functioning correctly.

If it is an '89 or older, the mixture screw should be at the base of the carb. You will need a vacuum gauge to help you adjust the mixture. You may also want to check that your choke is disengaging once the engine is warm. Do you stil have the heat riser tube coming up from the heat shield around the exhaust manifold? That tube should be going into the bottom of the air filter.

The ECU (computer) is under your dash on the right side. You may be thinking of the oxygen sensors in the exhaust pipe (depending on what year truck, you have one or two). You can clean those, but be careful, you can damage them too when you are taking them out.