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Post by LJScott on Mar 21, 2009 10:02:43 GMT -5
My 2005 GMC Yukon needs a tune up. In the current economic climate I like many others have tightened my belt and I am thinking of doing it myself.  I haven’t done one in 20+ years.  In a truck with electronic ignition what all do you tune up these days. New plugs is obvious, do you still set the timing and if so how? What else do you replace? I am assuimg no points to gap anymore? Any advice is appreciated. |
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Post by Scott on Mar 21, 2009 14:23:29 GMT -5
How many miles? I would use the owners manual's service schedule as a starting point. It will tell you what you should do in relation to the miles on your truck.
You no longer need to set the timing. It's electronic.
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Post by LJScott on Mar 21, 2009 18:21:42 GMT -5
It has about 60,000 on it. My guess is the owners manual will just say tune up although I will go look.
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Post by Scott on Mar 21, 2009 20:31:49 GMT -5
your plugs are good for 100k
Unless your having some kind of trouble don't mess with much. I'd say fuel and air filter, PCV.
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Post by johnsxj on Mar 22, 2009 21:10:45 GMT -5
You might want to check the condition of the cap, rotor and wires. Most of the new vehicles have platinum spark plugs from the factory (our '02 Chevy delivery van does).
Scott is right about the timing. The inside of the distributor now is just a camshaft position sensor.
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Post by LJScott on Mar 23, 2009 8:20:07 GMT -5
Thanks guys!
Gas mileage has dropped from close to 15 to more like 13 and there is some weird hesitating that goes on at certain speeds on the highway. I will check the air filter, rotor and plug wires and change if needed, swap out the PVC valve and fuel filter and maybe I will just pull a couple of spark plugs and check em.
Scott
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Post by Scott on Apr 3, 2009 20:08:05 GMT -5
I didn't notice you replied so sorry for my late reply.
If their is a hesitation I'd have the MAP sensor checked at a GM dealer or a mechanic that's familiar with these trucks. If the smallest piece of hair attaches itself to the sensor it will f' it all up. we had this problem with my wifes old (02) Yukon.
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Post by LJScott on Apr 10, 2009 9:52:05 GMT -5
I finally got a few minutes to look at this some more.
The owner’s manual basically doesn’t recommend any tune-up related items until 100,000 miles. I did check the air filter and it is almost new. It gets checked at every oil change so that is no surprise.
This is really the first time I have looked at doing anything on my truck engine. They really could make it easier to work on. Four big torx head bolts just to get to the air cleaner and the whole top of the engine is covered with three big plastic pieces that don’t seem to be there for any other purpose than to say Vortex 6000 in big letters.
So now the question is why the big drop off in mileage to about 13 mpg from a typical 15 mpg and highway hesitation problems? I could try swapping the pcv vale but is that likely to cause those kind of problems? Any other ideas?
I may have to take it to get looked at by someone who actually knows what they are doing.
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Post by marky on Apr 10, 2009 12:59:01 GMT -5
I hate to ask this question, but I'm assuming you've accounted for the cold winter months reducing your mileage? ;D
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Post by Jon W on Apr 10, 2009 20:12:49 GMT -5
I hate to ask this question, but I'm assuming you've accounted for the cold winter months reducing your mileage? ;D I was thinking that too... But I guessed that wasn't it from the timing of the post. How about tire pressure... If your tires got softer (lower pressure in cold weather) that could cost 1-2 mpg. JW |
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Post by Scott on Apr 10, 2009 21:47:40 GMT -5
Scott, Go to auto zone and have them see if there are any codes.
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Post by LJScott on Apr 12, 2009 12:35:48 GMT -5
Scott
I have an OBDII readre, I will hook it up and see if anything comes up.
Thanks
Scott
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Post by LJScott on May 6, 2009 10:31:13 GMT -5
Get this, it has no PCV vale and no fuel filter. Plugs look brand new.
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In a truck with electronic ignition what all do you tune up these days. New plugs is obvious, do you still set the timing and if so how? What else do you replace? I am assuimg no points to gap anymore?
