I want your old fuel pump. Are you willing to ship it to me if I pay postage?

 

lol, man i am NOT quick enough... never saw his fuel pressure post. [:@]

 

my old carb'ed chevrolet started to buck and pop when giving it gas and especially going up hills. It was rust coming out of the gas tank and clogging up the gas filter. As it would lean out it would buck something terrible. I thought it was blowing up. But then when you let off the gas it would idle fine. Good luck.

 

***UPDATE***
The new fuel pump is in and works great. It holds pressure and the truck starts much better now.

However, I am still getting the bucking problem at temperature. The CEL came on with a P0138 code. O2 sensor circuit high voltage (bank 1 sensor 2) indicative of low oxygen level. I cleared the code and ran it till it started its fit again (not too long). The CEL did not come on but the computer is holding a pending P0138 code. I changed the ASD relay and heater fuse. Ran it again. The CEL came on with the P0138 code.
Could I be correct in assuming that as the engine is warming, the PCM is in Open Loop Mode and ignoring the possibly bad O2 sensor (Running fine)? Then when the PCM goes Closed Loop, the signal from a bad O2 sensor is telling the PCM that there is low oxygen and adjusts the fuel/air ratio causing the misfiring?
What would cause the PCM to enter Open Loop again? The reason I ask is because sometimes after a time of misfiring in its fit, it will straiten out and run fine again.

There are only 2 sensors in my truck. One before and one after the cat.

 

What about that old fuel pump???

 

Sorry VWandDodge,
Someone from my buddys' race club asked for it. Kinda hard to say no when my buddy's under the truck turning wrenches with me.
Tim

 

Understood.

 

***update***
I think we've got this fixed!

Finally got a chance to change the O2 sensors. The rear (post-cat) sensor seemed to be the culprit of the bucking problem. It was producing a P0138 code. So far the new sensor hasn't coded at all. I'm gonna drive it a while longer tomorrow to test it for sure. I'll post results.
Thanks to all for their input. I've learned alot here.
Tim

 

Bad kitties go rattle, rattle, rattle!
All the way to work yesterday it bucked. Although the o2 sensor was bad and sending the P0138 code, it was not the source of the bucking. Last night at work we went to the parking lot and gave the cat a little shake, and sure enough it started rattling. It never rattled while I was driving or idling. This morning I checked the pre cat - post cat temperature, and it was higher b4 the cat during its fit. Thanks Steve, for the perfect timing of your troubleshooting post! https://dodgeforum.com/m_334375/tm.htm
In all the Fuel pump was bad (wouldn't hold pressure), the O2 sensor was bad and throwing a code and CEL, and the cat was clogged. I needed a new muffler anyway, so I have a Flowmaster Deltaflow 40 Series coming in Monday to connect to my brand new cat!
Merry Christmas to Timmy! I hope to put it all together next week before the holiday.

 

Isn't it fun how all of those things work out? Sounds great. Give us an update when you have the new exhaust.