TheMattBe
Newbie
Hello all!
2000 Tahoe Limited, 110K miles. The vehicle is in excellent mechanical & physical shape, lived most of its life in Arizona, Texas, & SoCal (no rust).
A few hundred miles after upgrading the fuel system to MFI, the vehicle began to exhibit a shuddering / hiccup symptom. In my best words, it feels similar to a sudden clunk/hitting a large road joint/going from R to D with a sloppy old transmission with bad U-Joints. It only began happening in OD, and diagnostics & feel were VERY convincing to a bad torque converter.
After a new converter from TCI, along with a remanufactured 4L60E from GM (for good measure), nothing really changed. The intermittent clunk is slowly progressing worse, now happening outside of OD, and increasing in occurrence from approx. 1 clunk in 5 minutes, to an occasional 3-5 clunks per minute, but extremely random and unpredictable, with sometimes no clunks.
With no stored DTCs, no CEL/SES, and seemingly no indication of any fault by the PCM, I'm at a loss. Before I data-log a couple drives and dig into the data, are there any suggestions on what to look for?
The Tahoe has:
-110K miles
-~8mo. old MFI upgrade system
-New fuel filter
-New TCI lockup converter, stock stall speed
-Remanufactured 4L60E by GM
-Brand new ACDelco Dexron VI fluid
-Very good mechanical shape, no rust, well-maintained
-Battery connections are good, recently remanufactured ACDelco alternator
-Once again, NO stored DTCs, no CEL/SES, and no real indication from the onboard diagnostics of any problem
Specifically, are there any PIDs I should pay attention to & log, any specific conditions I should check (Open/Closed loop, gear, etc), or any general advice before I dig into this? It could just be a coincidence that this started happening a few hundred miles after the MFI install, but could it be MFI related (bad injector, poor connection somewhere)? There is no specific budget for this fix, but I don't want to throw parts at it and hope for a fix.
Thank you in advance, and picture for attention!
2000 Tahoe Limited, 110K miles. The vehicle is in excellent mechanical & physical shape, lived most of its life in Arizona, Texas, & SoCal (no rust).
A few hundred miles after upgrading the fuel system to MFI, the vehicle began to exhibit a shuddering / hiccup symptom. In my best words, it feels similar to a sudden clunk/hitting a large road joint/going from R to D with a sloppy old transmission with bad U-Joints. It only began happening in OD, and diagnostics & feel were VERY convincing to a bad torque converter.
After a new converter from TCI, along with a remanufactured 4L60E from GM (for good measure), nothing really changed. The intermittent clunk is slowly progressing worse, now happening outside of OD, and increasing in occurrence from approx. 1 clunk in 5 minutes, to an occasional 3-5 clunks per minute, but extremely random and unpredictable, with sometimes no clunks.
With no stored DTCs, no CEL/SES, and seemingly no indication of any fault by the PCM, I'm at a loss. Before I data-log a couple drives and dig into the data, are there any suggestions on what to look for?
The Tahoe has:
-110K miles
-~8mo. old MFI upgrade system
-New fuel filter
-New TCI lockup converter, stock stall speed
-Remanufactured 4L60E by GM
-Brand new ACDelco Dexron VI fluid
-Very good mechanical shape, no rust, well-maintained
-Battery connections are good, recently remanufactured ACDelco alternator
-Once again, NO stored DTCs, no CEL/SES, and no real indication from the onboard diagnostics of any problem
Specifically, are there any PIDs I should pay attention to & log, any specific conditions I should check (Open/Closed loop, gear, etc), or any general advice before I dig into this? It could just be a coincidence that this started happening a few hundred miles after the MFI install, but could it be MFI related (bad injector, poor connection somewhere)? There is no specific budget for this fix, but I don't want to throw parts at it and hope for a fix.
Thank you in advance, and picture for attention!
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