Coming back from a long trip I noticed at 60mph the RPMs started jumping and the transmission was dropping in gear and back up. I fully cleaned the throttle body and mass air flow sensor. Same thing, RPMs jumping. I changed spark plugs about 20k ago, but didn't do the wires. I just replaced the spark plug wires and still, the same thing. What else should I do? No codes to go by.
RPMs jumping when driving
- Thread starter Matt1t
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Jake707
Member
Is it like a stutter/surge from possible fuel delivery issue or more like a miss from either a sensor spazing out of wires arching, since you replaced those plug wires I would assume not this exactly but still a type of "feel" when driving if that makes sense haha.
Joseph Garcia
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You say that you have no codes. Are you using a quality bi-directional scanner, one which accesses deeper levels of the systems and identifies their codes?
I really don't know. I guess I'd say it feels like of a miss. Its somewhat sporadic which is irritating.
No check engine light. I have a older ScanGauge device I've used for some time. To say its a quality bi-directional scanner, I'd say not but its what I got.
Generally rpm surging is the transmission slipping, unless you are getting hard vehicle bucking along with the surge which would possibly be maf related, fuel pressure or any other variety of engine problems. If the rpms are all over the place and you are not getting tossed around like a bull rider then I would be taking a hard look at the transmission
strutaeng
Full Access Member
Transmission slipping would be increase in RPM without a corresponding increase in acceleration or speed. Is that what you have? It's the engine is revving and you are in neutral.
My 2009 Tahoe LT 5.3 l 4wd 6-speed automatic had its transmission fail just two weeks ago. 253 k miles. I first noticed there was something afoot that morning, nearly 540 miles from home. The tranny was shifting weird (not doing its standard pattern, sometimes late on a gear change, sometimes early, unnecessary rpm surges, very minor stuff, but the kind of thing that is quickly noticeable), had to fuel in Palm Desert CA, when I exited the freeway to get gas, it dropped out of gear, took a bit of effort (going to park, neutral, drive, manual) made it to the gas station. It was def unhappy at the station, was able to coast to an open parking area. Transmission would occasionally engage, but not for long. Ended up being a 265 mile tow home and a new transmission. Thanks goodness for AAA Premier - ended up arriving home only 2 hours late! 
Good luck! Cheers - Jon
Good luck! Cheers - Jon
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Hmm, thanks for the reply and yes I thought about the transmission as well. It doesn't seem like its slipping but what you have listed does get me thinking as its just doesn't feel right in the shifting patterns. Oh, and I will add that no hard vehicle bucking or surges have been noted. Sure hope its not the tranny. On person recommended a whole new thorttle body and throttle body sensor. I believe its all in one.
