# 99 yukon 350 vortec loss of power?

**URL:** <https://community.cartalk.com/t/99-yukon-350-vortec-loss-of-power/38330>\
**Category:** Maintenance/Repairs\
**Tags:** gmc\
**Created:** [October 19, 2009, 7:36pm UTC](https://community.cartalk.com/t/99-yukon-350-vortec-loss-of-power/38330 "2009-10-19T19:36:13Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![44magman](https://avatars.discourse-cdn.com/v4/letter/4/54ee81/32.png) [@44magman](https://community.cartalk.com/u/44magman)\
**Post date:** [October 19, 2009, 7:36pm UTC](https://community.cartalk.com/t/99-yukon-350-vortec-loss-of-power/38330/1 "2009-10-19T19:36:13Z")

</div>

when floored to pass or just kicking into low gear, engine races but not the rest. don’t think it’s tranny. Disconnected MAS sensor and it went like a bat of hell. sadly, that was short lived. bought MAS cleaner and made very slight difference. HELP

---

<div class="post-metadata">

**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\
**Post date:** [October 19, 2009, 8:38pm UTC](https://community.cartalk.com/t/99-yukon-350-vortec-loss-of-power/38330/2 "2009-10-19T20:38:00Z")

</div>

Does the check engine light come on?

The MAF sensor can be tested. Don’t just throw parts at it.

---

<div class="post-metadata">

**Author:** ![roadrunnr43](https://avatars.discourse-cdn.com/v4/letter/r/f1d935/32.png) [@roadrunnr43](https://community.cartalk.com/u/roadrunnr43)\
**Post date:** [October 19, 2009, 10:24pm UTC](https://community.cartalk.com/t/99-yukon-350-vortec-loss-of-power/38330/3 "2009-10-19T22:24:33Z")

</div>

fuel injector cleaner.if you’ve been eking out all the mileage you can get, you have crap all over the injectors. or the clutch discs have gone south.

---

<div class="post-metadata">

**Author:** ![44magman](https://avatars.discourse-cdn.com/v4/letter/4/54ee81/32.png) [@44magman](https://community.cartalk.com/u/44magman)\
**Post date:** [October 19, 2009, 10:39pm UTC](https://community.cartalk.com/t/99-yukon-350-vortec-loss-of-power/38330/4 "2009-10-19T22:39:19Z")

</div>

thanks for the advice. my mechanic said he will check it out.

---

<div class="post-metadata">

**Author:** ![44magman](https://avatars.discourse-cdn.com/v4/letter/4/54ee81/32.png) [@44magman](https://community.cartalk.com/u/44magman)\
**Post date:** [October 19, 2009, 10:41pm UTC](https://community.cartalk.com/t/99-yukon-350-vortec-loss-of-power/38330/5 "2009-10-19T22:41:07Z")

</div>

been running 3 tanks of premium fuel and have tried injector cleaner. any suggestions on a “good” brand name??? thank you.

---

<div class="post-metadata">

**Author:** ![roadrunnr43](https://avatars.discourse-cdn.com/v4/letter/r/f1d935/32.png) [@roadrunnr43](https://community.cartalk.com/u/roadrunnr43)\
**Post date:** [October 19, 2009, 11:42pm UTC](https://community.cartalk.com/t/99-yukon-350-vortec-loss-of-power/38330/6 "2009-10-19T23:42:26Z")

</div>

any brand should work. the RPM’s rise, but doesnt go any faster, is that correct? how about your buddy, RPM’s go up but no speed?

you could have a weak spark or low fuel pressure.