MAF accidentally left unplugged, tune fubar'd?
04-06-2009, 02:38 PM
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MAF accidentally left unplugged, tune fubar'd? this is on my GMC truck. I was running at the track without my air filter and forgot to put it back in on the way home. I get it back in the next day but forgot to plug my MAF back in. Got a po-102 SES as one would expect, plugged the MAF back in and reset the PCM. SES light off. But ever since then my 1-2 shift has become soft, mushy as hell, really horrible. It's normally very snappy and quick. My truck also seems to be more sluggish??? The 2-3 shift appears unaffected. But overall it feels like crap. I've left the battery unplugged and reset the pcm with no luck. Thoughts? 
04-06-2009, 03:15 PM
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Depending on the year of the calibration, some early 1998-2000 F-bodies, and I think all trucks, would revert to full line pressure if the MAF failed. So experiencing hard shifts now just means it is using the shift pressure tables, rather then full line pressure. If you like it that way, just set the trans to full line pressure or up it to your desire. Be cautious if your trans is not built.
04-06-2009, 03:21 PM
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Ive got another pcm I'm going to stick in and see what happens. I will report back. I did go to the track and pounded on my stock 4l60e, so I assume it's possible it got damaged. However, it drove home perfectly normal from the track.
