I have a 2001 5.4 triton with 210k miles on it. After some reading I decided to clean Throttle body and MAF as it had never been done in the life of the truck. Still idled fine before the cleaning, just thought it would be good to do.

Now the truck has a slightly rougher idle. When the engine is revved up and rpms fall under 1000, they erratically shoot back up to around 1400 then fall back to 700 and bounce around until it finally settles at 600 rpm idle. The engine never used to do this. Hope y'all wise minds have an idea of the problem and a possible solution. Thanks.

 

Clean the IAC.

 

Did you remove the IAC from the throttle body when you cleaned it? If not, all that junk was washed into the IAC

 

Did not remove the IAC. That makes sense though. I will clean it and see how it goes

 

For that to happen, -something got messed up. Certain cleaners will do that. Destroys the TPS ribbon, EGR diaphragm, -even the plunger seal inside the IAC.

You can't use harsh cleaners on the TB with these sensors and valves attached. You'll smoke them for sure.

Also, - if you removed the throttle plate, -you need to know how to reinstall that correctly. Its not just a simple, -screw it back down unfortunately.

 

I used throttle body specific cleaner and followed the directions on the can then wiped out the throttle body. Would IAC be a good first thing to check? And would it be a good idea not to take the tb apart at all if its not a simple screw back together?

 

I would guess that the instructions mentioned to stay away from rubber seals and sensors...?

Yea. IAC first. Jbrew is speaking of the throttle plate... if it was removed, there is a procedure for reinstalling correctly. Removing and cleaning the TB is not an issue. If you are fully dissembling the throttle body, different story.

 

Yes they sure did. When I smelt the cleaner I knew not to let it touch anything else. That is some potent stuff. I have the day off so I'm tearing into the iac soon and keep my fingers crossed that solves it. Would it be fine to just clean it out or better to go ahead and buy a new one?

 

You would probably be fine just cleaning it but at 210,000 miles I would be inclined to get a new one.

 

Use WD-40 to clean the IAC.