My engine won't stay at a steady speed. Please help!

[jcfreeman0]

My truck starts and idles fine. When I first take off everything feels great. When I get to 4th gear and want to stay at a certain speed the engine bogs out / slows down unless i give it some more gas. Then its choppy unless I really get on it until I turn it off and let it sit for a minute. Then the process starts all over again. Once it gets choppy like that it backfires and what not as well. Does this sound familar to anyone? What should I check?

It appears to be getting fuel pressure. When its idleing and I rev it enough until it starts boggin out the fuel stays right at 58psi. Its basically doesnt move from that psi at all. I cannot see my gauge while i'm actually driving though.

[skeet]

My truck starts and idles fine. When I first take off everything feels great. When I get to 4th gear and want to stay at a certain speed the engine bogs out / slows down unless i give it some more gas. Then its choppy unless I really get on it until I turn it off and let it sit for a minute. Then the process starts all over again. Once it gets choppy like that it backfires and what not as well. Does this sound familar to anyone? What should I check?

It appears to be getting fuel pressure. When its idleing and I rev it enough until it starts boggin out the fuel stays right at 58psi. Its basically doesnt move from that psi at all. I cannot see my gauge while i'm actually driving though.

have you changed the spark pluga recently?

[RUFFNECK]

Might check to see if your TCC is engaging and disengaging on command. Sounds like a shudder.

[farmtruc]

Here's my opinion, it might help.

You say it clears up after you turn the truck off and then start it, then get up to speed? When you turn your truck off, then on, your pcm goes back into open loop when you first turn it on, then after about 30-60secs later, the pcm will go into closed loop, at which that time the O2's are trying to work and give feedback to the pcm. If one of those O2 sensors are stuck at 400-600mv's, it's considered a lean condition and a bad O2 sensor.
Backfires and stumbling will occur with a bad O2 in closed loop, I see this quite a bit.
If you have access to a scanner, check the O2 voltage at idle or cruising, if they are at 400-600mv and not toggling from 50-900mv, then the O2 sensor is bad.

Definitely sounds like a bad O2 sensor.

hope that helps,

[jcfreeman0]

I had a guy scan it for me. He said it wasnt throwing any codes up. He said the o2 sensors were working fine. I just had him scan hit while sitting on the trailer (not while driving). He also told me it stayed in open the whole time it was hooked up (about 5 minutes) He thought by my description it was running lean. He questioned my fuel rail set up but he thought that thing on the stock rails was the regulator but to my knowledge its a fuel dampener.

My current setup goes walbro 255 - pp fuel pressure regulator - fuel rail (the fuel pressure reg has a return on the bottom of it back to the tank). Does this sound right? Do I need to get a new rail set up. If I do are the pp pt# 10611 ok to run? Do I hook it up like this walbro - fuel rail in - fuel rail out to regulator - tank?

[jcfreeman0]

I took that regulator out of the fuel rail, pulled out all the plastic and spring, cleaned it really good then put it back together. She runs perfect now! It makes sense now in hindsight. The first regulator was set at 58. So the fuel rail only had 58psi going to it and it couldnt keep up. Not to mention it didnt have a return after that second regulator. Its all good now though. Thanks everyone!