Ok so i did my timing the other day..and i noticed when the motor is cool it runs 100 percent better than it did..BUT once it warms up it will knock if you keeop the gas at a certain point..but wont really knock when you floor it...any ideas??

 

try good gas, 91 octane and up. smell your exhaust, maybe your cat is plugged, anyways remove it. its sucks.

 

I'm betting that your advance isn't working. Does the truck have an electronic advance or does it still have the old vacuum advance? And when you set initial timing, did you do it with the vacuum/electronic advance disconnected? Also, have you checked the condition of the counter weights and springs on the mechanical advance under the rotor?

And what good advice to remove the cat... I don't think so.. While it is possible that it may be clogged, a working catalytic converter is much better for the environment, not to mention that it may cause the vehicle to fail inspection depending on where you live. In NJ, if the inspector were to look, it would fail without a cat. And before you say 'gut it', that will perform worse than a properly functioning catalytic converter. If you need me to explain it further I can.

A clogged catalytic converter should exibit symptoms even when cold, typically higher up in the RPMs... Basically like the engine is being choked off. It will get worse when hot.

 

well there are 2 electrical connectors to the distributor so i am guessing electonic advance..now when i did it the instructions said to unplug the tan/black wire from the bulk head...well i couldnt find any such wire..so i did the timing without unpluging anything..i drove it around the block..threw the timing light back on and it was still good...so i am guesing it really didnt need to be unplugged...and how would i check my counterweights and springs??