2006-12-27 05:43:38 · 4 answers · asked by Anonymous in Cars & Transportation ➔ Car Makes ➔ GMC
the check engine light was on. the advance auto parts store put it on the computer. they said the upflow O2 sensor needed replacing. I bought it. the car had some hestitation at first. ran okay at a 65-70 speed. i also had the plugs, rotor button, dist cap, fuel filter, air filter replaced.
2006-12-27 05:56:43 · update #1
There is at least three oxygen sensors on this truck. There will be one in each of the exhaust manifolds or the down pipes before the cat. convertor. There is another sensor on the cat. convertor outlet. An oxygen sensor will not normally cause a hesitation. You said you did a tune up so that is eliminated. As long as there are no codes in the system, you should be looking at some other type of maintenance. These motors were famous for sticky injectors, so a thorough cleaning might be required. These motors were also famous for leaking gaskets on the upper intake. This might not be diagnosed by the computer if it is a smalller leak. You could also have a leaking CPI unit. This was the biggest problem with this motor. This is the injection unit located under the upper intake. This usually causes a hard start, hesitation problem, poor gas mileage, and others. The thing that makes me say this is because the oxygen sensors do usually pick this up and will either set codes or try to lean out the mixture due to the excessive gas in the intake stream. You can determine this problem with a fuel pressure leak down test. To be absolutely sure this is the problem, lift the upper intake off and inspect the lower inside of the intake. If there is an internal fuel leak, the lower intake will be absolutely clean of any carbon deposits compared with the other side. If both sides are clean, both sides are leaking as there is usually a bunch of black soot/carbon deposits in here.
2006-12-29 10:36:26 · answer #1 · answered by Deano 7 · 0⤊ 0⤋
Has 3 possibly 4 o2 sensors. One on each exhaust manifold ( the upstream sensors ) and one after each catalytic converter.
What is the problem with the vehicle?
2006-12-27 05:48:12 · answer #2 · answered by Don W 6 · 0⤊ 0⤋
Follow your exhaust from the engine toward the back where the pipes meet from each side, at that point there should your o2 sensor within a foot from where the pipes meet. not a lot of space to get at it though.
2006-12-29 05:36:20 · answer #3 · answered by quik1964 3 · 0⤊ 0⤋
It's either in the exhaust manifold or in the exhaust pipe, right below the manifold.
2006-12-28 16:38:45 · answer #4 · answered by Eye Candy 3 · 0⤊ 0⤋