Joined: Sun Mar 11th, 2018
Reputation Points: 174
|I'm trying all the Ford Ranger boards for as much information as possible on determining the cause of my idle drop down and miss at stops. The RPM drops all the way into the 500's when I come to a stop light or stop sign. At different times during these stops it will also have a slight miss felt. In the past few weeks all ignition has been changed to new Motorcraft ignition parts including coils, plugs, and wires. In the past year battling the same slight miss every sensor has been replaced with new Motorcraft parts and every test you can think of has been done to the engine. I have a Harbor Freight scanner and an ELM tool using the latest Forscan software to see what's going on. I don't have any stored codes or CEL on. Neither tool I have has access to a cylinder balance test. So I was reading online and found out that Mode 6 Test 53 would show which cylinder's had misfires. According to the results I pulled yesterday and today I have #3, #4 at 0.24%. I drove all over the place yesterday and today but it's still the same % number. So I'm wanting to know more about Mode 6 Test 53. How often does it update? Doesn't seem like it should be so exact to be at 0.24% all the time. I downloaded the OBDII theory explaining each Test in Mode 6 from the Motorcraft website but it's so complicated to understand. So if the ignition is all working on those cylinders, cylinder compression is 140 PSI on all 4 cylinders, fuel pressure is 60-62 PSI, vacuum is 16 In Hg at idle what else could I check to see why those two cylinders are misfiring? I've been to numerous shops and even Ford with no one being able to help.
1998 Ford Ranger XLT 2.5 4R44E Automatic 4.10 non-limited slip, 1993 Ford Ranger XLT 2.3 M5 Manual, 3.45 non-limited slip