97 F150 4.6 200xxx on recent rebuild

Hey all, so my truck is throwing P0171 & P0174.

I think I tracked it down to leaky IAC and EGR gasket. I sprayed both with carb cleaner and the RPM's dropped.

My question is, wouldn't the RPM's rise instead of drop? I was under the impression that they would go up if the gaskets were leaking. Or did I use the wrong spray?

Thanks

 

Don't worry about the reaction, fix the leaks.
Good luck.

 

at an idle carb cleaner can choke out an engine, whether rpm's increase or decrease its the fact that spraying that isolated spot is causing an rpm change that is key, some brands of carb cleaner burn better than others, and from my limited experience fi systems don't like c/c at an idle

 

heh i type to slow, bluegrass's post wasnt there when i started typing :P

 

Thanks for the replies all, my curiosity was getting to me