About 2 months ago my 2000 5.3 Silverado started surging in OD between 40-50mph. I haven't been able to track down what would cause this. I have run FI cleaner through and it still happens. Any ideas out there???

 

shift solinod out?? have you had it scaned yet? low trans fluid? any tuning on the truck yet?

 

sounds like the converter is slipping in/out of locking up a little

 

No, I haven't had it scanned yet for codes. No one around the area does "free" scans. It acts like someone is lightly pressing the throttle and then letting up. The problem is it doesn't do it all the time so it is hard to put any pieces of the puzzle together. Of note I do have a Jet PowrShift on it, but I wouldn't think that would be causing the problem.

 

That's exactly what happened when I put in my built trans and stall. 40-50mph it would seem to go in and out of lockup. Sounds like the exact problem. My trans blew 1st gear after 3 days so I never fully diagnosed why it was doing that. Hopefully the new one won't...

 

2K 5.3 with what mods? Is is a built tranny? 4wd? still have 4l60? Found yourself a good reason to buy a scan tool or have a local shop get what codes you are showing (I am sure you know not all codes have to throw a SES light). If you are showing an "Incorrect Correct Gear Ratio" code this means you either have a bad TCC solenoid or a bad speed sensor. Most likely the speed sensor? How many miles? Might be simple with the FI cleaner, but the PCM will throw a light for any emission related stuff, so it's probably not a good chance. I suggest getting any engine codes if there are any first to establish a game plan. Especially if you are stock. If your mod'ed, finding the issue might not be as easy.

I just fixed my surging, exact same description as yours, on the scan tool you'll see the TCC locking and unlocking. The 4l80 has it's own speed sensor...input sensor was bad. Runs great now.

 

No mods except for Flowmaster American Thunder exhaust system and Jet Powrshift module. I'll see if I can find someone who will check for codes for a resonable price. How much was the fix on yours?

 

where do you live? Maybe someone from here has a scan tool to help you out. Next thing i would check is the chip you have on the trans disconnect it and go back to stock and see if the problem still there.

 

auto zone scans for free.


this may be a little too basic, but have you switched what gas you use? When I run regular it does that same thing.....

 

I live in San Angelo, TX. I'm going to try disconnecting the Powrshift and see what happens. As far as gas goes I'm in the military and buy 95% of my gas on base. I"ll keep all ya'll posted..... Thanks for all the help!!