Iloveaxles

Recently put a new engine in it because the last one blew. The piston cracked and gouged the cylinder wall beyond repair but the cause was something about a error when it was made from the factory?? Put a 4.0 from junkyard in it. It sounds terrible and shakes bad sometimes but it doesn't knock or anything. But it sounds like a sewing machine hahaha isnt that normal with 4.0s? Anyways when it idles itll idle fine than it will idle up almost like your tapping the gas. Anyone know how to fix it? Does it just need the throttle cable adjusted?

dave1123

It may need a new TPS (throttle position sensor). They tell me there is a small vacuum hose in between where it mounts that may have a crack in it. Oh, wait! Maybe that's the IAT (idle air control). Whatever, all the vacuum hoses may need to be replaced because of the engine sitting for a long time. Also check the throttle body mounting gasket for vacuum leaks.

Iloveaxles

Thanks man. Also the transmissions been slipping. Its automatic. How do I fix it and whats the cause? Ill just ask you since you seem like you know your stuff.

dave1123

I'm sorry, it's the IAC, not the IAT.

With the transmission, other then being low on fluid, there isn't much to do about slipping besides a rebuild. You can have it checked for governor pressure and other things in a shop.