Running problem

[fastergrass]

I have a 94 ranger with a 3.0 4x4. When I start the truck it runs fine. I then have to let idle for about 5 minutes. Then it's seams to run poorly for about 2 minutes then clears up. I am also have codes pop up saying spark timing wich is dead on. and saying back pressure sensor not in range I have replaced the distributor 2 times and back pressure sensor about 5 times. Voltage is with in specks. I would like to know how much vacuum it takes to open the egr? It opens when not needed. What's going on!!! ??? I'm starting to lean towards the pcm. I'm so lost? and I have replaced all sensors known to man on the thing...... ugh

 

[enjr44]

In computer talk the sensors are telling you that the inputs the computer is getting from them is out of range. NOT that the sensors are bad. A back pressure sensor out of range is usually caused by a bad part in the exhaust system. Something that can cause back pressure.

Others will chime in on the rest of it.

 

[fastergrass]

I have gotten all but the egr fixed. Someone told me that the egr tube should have a small restriction in between the two ports that go to the back pressure sensor. If so what size is that restriction? I had to make the tube to keep costs down and that Dorman at the time did not have the one I needed