Black build up in the top chamber

[Phx_Pathy]

So, lately, my MPGs have dropped. So, I start looking first at my intake system. I replaced a tiny hose from the air filter housing that was cracked. Then, I still noticed a slight lag in acceleration when i'm already driving. Off the line, i still got power. But, while i'm driving, she has a bit off a lag response. Well, looked again at the air intake and made she the whole assembly was ok and it was. No cracks or anything, but, when i looked into the chamber, there was a build up of black sludge. I then looked at my exhaust and noticed that the tip of the exhaust was also black. I'm kinda worried about this? It's 98 Pathy, SE, Auto. Any ideas? I didn't change my oil in August and the air filter is just fine. Would love an explanation or some advice to where to look?

[smj999smj]

Varnish buildup in the throttle body and on the throttle plate is common over time. Throttle body cleaner and a soft rag can be used to clean out the varnish. After cleaning, hold the accelerator pedal to the floor when starting as it will likely act like it's flooded due to the cleaner getting into the engine. I usually do this every 30000-40000 miles.

[Phx_Pathy]

So, I should buy a can, open the throttle plate and spray? Or, should I get inside and get more thorough?

[unmeloy]

So, I should buy a can, open the throttle plate and spray? Or, should I get inside and get more thorough?

the best way to do this is to take it off all together and clean it thoroughly... unknown if there is a pcm or ecu relearn process after taking it off... what i would (have) done it... take off the throttle body after disconnecting the battery. unhook all electical to it. clean thoroughly and make sure it is fully dry. reinstall and hook back up like originally. attach battery. turn ignition to on position only and allow to sit for 10 min. then start and let idle for another 10-15 min. should allow the system to reset and "relearn" your cleaned throttle body.

have used this method on several vehicles.

[smj999smj]

There's no relearn required on the VG engines. I just remove the air duct, turn the throttle drum by hand to open up the throttle plate and give it a good spraying. Then, I take a soft cloth and wipe it out.

[Phx_Pathy]

What's your opinions on Seafoam? I've heard it helps tons? Is it really worth the rave? If so, do i feed it directly using a line from the brake booster?