OK, I have a 95 ranger supercab 4wd 4.0L V6 MT. I have had a check engine light on for a little while and it did not bother me too much since the engine was running fine. A couple of months back I started to hear a ping - and had been meaning to look into it.

Well, a couple of weeks ago the truck started to stall when it would go from high-low idle when cold. I cleaned the IAC which did not help. I decided to clean it one more time and ended up cracking the diaphram - so it is now replaced. I also checked/cleaned the MAF (it looked fine). I believe the idle is now fine - however I need to try it a few more days before signing off on it.

I still have a check engine light. I have ordered an OBD II scanner so I can stop guessing, however I did have a question on the DPFE. I read the test procedure on the technical notes link. Step 9 says the VREF should be .5 volts with KOEO and hoses connected. Is this correct? Mine measured 5 volts, and to be honest, that makes more sense since it appears to be the input and there should be not be a voltage drop before that point.

I am measuring it from VREF to ground. Should I measure from VREF to sig ret instead? The DPFE SIG measures a consistent 1.3 - 1.4 volts (KOEO or with engine running). I want to get a hand vacuum to check it under pressure.

edit: misread door ajar section

 

sounds to me like it needs the throttle body cleaned out good as far as the high to low stalling goes.

 

If you clean the TB, clean out the intake manifold also. it can get pretty nasty in there (carbon buildup).