97 Ram 1500 5.2 NO START

Im pulling my hair out. The truck was running fine at 65 MPH then just lost power and slowed down to about 15 then stalled. fuel pressure is at 49 psi and 52 while cranking. Its got a good blue 3/4'' spark. I have lifted the fuel rail and the injectors are working fine. I removed the plugs and replaced them because 4 were fouled. Compression is 110-120. The only way you can get it to fire at all is cranking at full throttle it fires for a split second and dies every time. If i unplug the injectors i can get it to run on carb cleaner for a few seconds. I tried an ecm (same year same #)and map sensor off of a running truck and still the same. The only codes are misfire codes. The ignition system seems to be fine. Timing light shows number 1 is firing at 3 degrees or so. how is it posible this thing won'r run. any help would be great thanks.

Without being there to look at it, the first thing i'd do would be to inspect the distributor, cap, and rotor. Does the timing light show 3 degrees before or after TDC. I'm not real familiar with this engine, but 3 degrees before OR after TDC seems a little late.

Another thing that may be the problem is the timing chain. Spec. charts show it can't have any more than 1/8" slack.

Thank you corning. I just found the problem. I loosened the exhaust flanges off and away she went. I've Never seen a converter plug so fast and that bad before. I still don't understand why it would run on carb cleen. Thanks again.

Wow, that is wierd. One of the reasons they clog so fast is a rich running engine, which causes the extra fuel in the exhaust to be burnt in the converter, and melts the stuff inside the converter.

How many miles on that truck?

How many miles on that truck?
Its got about 341,000 k'ms. 215,000 miles.

That cat lasted a real long time.