1990 Ford Ranger XLT idleing really low

[skullz696969]

I have taken off my Muffler and replaced it with a cherry bomb and now my idle is around 500 rpm and it will sometimes just shut off completely when idleing. What could be the problem?
Thanks

 

[BBreidhaupt]

it could be one of 2 things but it will most likely be both things. youre muffler creates a significant amount of back pressure and back pressure is required for the function of the egr system and a stock motor needs the back pressure also. most usually ford ranger and explorer engines were notorious for egr problems when modifying the exhaust and in most cases will dump all the exhaust gases in to the engine causing a low idle or stalling the engine.