I have an 08 GMC Sierra with the LMM. It bucks, surges, and cuts out while accelerating. I don't have any codes or lights. The problem started off as a interment problem but has continued to get worse over the last 1000 miles. Has anyone had anything similar or any suggestions on what to check?
Make sure your air cleaner is clean. Get some MAF cleaner and clean your MAF sensor and he MAP sensor. See if any improvement. Do you have a functioning EGR? Maybe that's leaking.
Apparently I'm as bad a hitting post as I am send on text messages 🤣 It's got a brand new air and fuel filter, and the EPA stuff fell off in a mudhole.
An issue I think I am noticing is that when the "EPA" stuff is deleted, despite tunes to address it, the truck may never truly run right. Uggh. When exactly did you start noticing the issues? Was it after something special happened such as an oil change or service or heavy towing? How are your batteries? How is the MAF sensor (or whatever they call it now) How many miles on the truck total?
Figured out the problem finally... The ECM is loosing connection to every damn thing and for some reasons n it never set the light but after hooking a more expensive scan tool up and monitoring it while she threw her fits you could see the systems one by one fail and come back. Now to chase down the source, if I have to guess I'm going with bad ECM, bad connection to the ecm or possibly a broken/crushed wire.
What fid you finally find and fix? I have the same issue and cleaned tank, and filters. It seems electrical/computer rather than dirt as the speedometer, horn, readouts are intermittent.
Thanks.
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