I have a 1991 Ford ranger. It ran fine when I bought it. It up and quit me one day. It sits for awhile and it will start and run just fine for a little bit and konks out again. I have replaced the feul pump,ignition module and coil packs to no avail. would appreciate any suggestions.

First thing to check is the codes. Autozone has a code reader (reader of the 91 is rather cheap) The next would be check fuel pressure. I get a feeling that your are seeing fuel pressure starvation. (fuel filter) Get/borrow/buy a gauge, screw it on to your fuel line and let it run. before it dies, you will see the pressure drop like a rock. There is also the pressure regulator, but it doesn't usually work like that. What happens is the pressure builds up slowly because of clogging. as the truck runs, the fuel pressure goes down faster then the pump can keep up. That also explains the knock. Now since it is a 91' you could have a clogged catalytic converter/exhaust. Does it get warm then die? At the very worst you can have a cracked head and when it heats up the water squirts into the cylinder causing initial knocking, but it doesn't usually happen that fast and takes a while before that happens. Please let us know when/what you find out. Chris Robertson Christopher.T.Robertson@...