Judie

Hi again the shuddering was before the tune up, that is why we ended up getting the tuneup.. I think the first shop had no clue what they were doing, the second was for exhaust and that was fine and the latest one the guys is salt of the earth so he kept it real with me and so from the current shop they had replaced 02 sensor pre catylst i believe and it was still shuddering, but the engine light was not on, then they put in new spark plug wires as when they tested the existing ones (that were done in August 24) they were arcing and he also added a differential additive because he's had a customer with a similar problem recently and doing the additive has helped. So i picked up the truck yesterday afternoon, no engine light on and it seemed to drive good, better than ever really. Today it will go on the highway drive to really test her out. But the mechanic and I talked for 20 minutes about the truck, he has owned teh last 4 models of this truck same as us and we both feel basically there is probably still an underlying issue but until it breaks we cannot 100% figure out completely I think. If it ends up being a transmission break then I will not be replacing it with GM one it seems to be the same, it will be a rebuild with better components. thx

yes there is alot of people handling this truck in the past 6 months throwing parts at it as the different codes come up with the engine light going on and sometimes flashing, there are approx. 220km on the truck it is the v8 5.3 6 speed no problem was before tune up was in Sept24 and was because truck did not feel right, thats why it got the tune up was thought it would fix problem when it was driving it had the shudder, and it still has it when it was driven yesterday but only under doing 80km and now no engine light on since they put in an 02 sensor transmission fluid was change at around 190k also before tuneup truck had 02 sensor replaced and trailer brake controller replaced

HI everyone currently having shudder issues with my husbands 2018 GMC SIerra, took it there they wanted to replace the transmission over $10k and cam shaft another $3k needless to say we took it for quotes, for reference the recent truck maintenance has been a new tow plug, then spark plugs, wires and coils ya know a tune up, so then took it to a transmissin shop for quote, he said it wasnt transmission issue but it brought up these codes PO 326 knock sensor & PO 6B6 control module knock sensor, so took too shop close to home and they replaced knock sensor, we pick it up and engine light is on still they couldnt get it to clear, they wanted over $2k for exhaust repair, so i took it to exhaust repair fixed as it had a ticking sound from muffler and leaking mesh pipe weld on connnection i cannot remember what it is called, so left there no lights on then it came on was shuddering immesnsely undrievable had flashing engine light on, had it towed to yet another shop and they replaced the 02 sensor drove it 2 hours no light on but on the wah back it still shudders, what are we missing? and my husband is hard of hearing fyi so hence why he did not hear the exhaust issues that were fixed. thanks for any advice you can give me to help its been 2 weeks in and out of shops.