I have a 93 K1500 4x4 with a 5.7. 160,000 miles on it.

For the last few months its been running rough. I thought I had water in the gas so I have been running heat and Lucas through it. It lessoned but never went away. As I would go down the road it seemed to cut out for a second and then would run fine. It seemed to do this more going up hills.

Then the last 2 weeks it started running really bad. Backfiring, loosing power up hills, shaking, cutting out for a second multiple times.

Today I changed the cap, roter and all the plugs. There was no change after doing this,m still ran the same. I changed the wires a year ago and still look fine.

When I turn the key to the on postion the fuel pump kicks in and sounds normal. Next I pushed the gas pedal to the floor and cranked the moter over for about 30 seconds and it sounded fine. I am not getting any check engine lights and have not gotten any since this started happening months ago.

Any thougths as to what to do next?

 

UPDATE

I just did a fuel pressure test and I have 11psi when running. From what I understand with a throttlebody injector it should be between 11-13psi.

 

I think I solved the problem. I changed all the plug wires and it seems to be running fine. It has it's power back when I hit the gas. It still looses power when it shifts through the gears. That may be from it being low on gas. I'll fill it up tomorrow.