I am a votech student and i am trying to fix a 95 Ford Ranger 2.3L for my cousin. The engine has a rough idle and leaves a smell out of the exhaust like its running rich but theres no black smoke. For whatever reason he had to change his head and ever since then he's had the problem. He changed the MAF and O2 sensor and that didnt fix anything. We used a smoke machine to check for vacuum leaks and smoke came out of alittle round piece on the IAC valve and some out of the EGR valve, could that be the problem??? We used a scanner but he already deleted the codes so we didnt get any problems off that. I would appriciate it if someone could help me out here.

 

Welcome to FTE!

The test smoke coming out of the IAC & EGR assemblies probably means unmetered air is getting introduced into the system, which can defintely cause idle problems. However, overall this usually results in the system running lean, and not a rich condtion as you describe.

Just a guess, but maybe the PCM is taking the "system lean" feedback from the 02 sensors and then heavily compensating by dumping more fuel into the chambers...