94 GMC Safari AWD

I am still getting poor mileage 400km per 80 liter tank. I have the v6 vortec with the w engine. The truck runs perfect but sure sucks the gas. It Starts hot and cold
with the flick of the wrist. It has a perfect smooth idle lots of power. When cruising down the hiway I am barely on the pedal.
It was worse before I did some repairs now I am stumped. The idle exhaust smells strong not like unburnt gas but like an old sixties v8. Here is what I have done: Checked for codes none found. New air filter, cap, rotor, plugs, wires. Fixed leaky vacuum lines. set timing. Replaced the o rings and CPI unit inside of intake. (ouch $708.00 dollars CDN) I removed the electronic EGR valve it seems ok it moves free and no clogging. I found the fuel tuning valve stuck and fixed it.
I would like to know how do I test the o2 sensor and egr etc. with a VOM? Is there an Eprom that might help me also?
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My uncle has a 1999 Safari AWD and his mileage is the same. There may be nothing you can really do about it.
(248.56000 miles for 21.13383 gallons)
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I ran across this tid-bit of info:
SENSOR MALFUNCTION Measure air temperature in the intake manifold and signal computer to adjust air/fuel mixture. FAILURE SYMPTOMS light is on continuously, poor mileage or rich exhaust odor, poor performance and economy. MAINTENANCE/SERVICE Inspect for damage or corrosion on terminals when trouble codes indicate problem in this circuit. Check sensor for carbon accumulation or contaminants which can cause false readings.
1234 wrote:

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1234 wrote:

I did it! I am now getting 700 kms per tank. After doing everything above I finally took the o2 sensor out. Removel was easy with a six inch cresent. What I found was the little probe about the size of the end of a baby finger. It had about ten little slits in it and 3 of them were plugged with carbon. I crudely scraped them out with a box cutter knife shot it with wd40 and put the sensor back in. I filled the tank and hit the hiway doing about 115 kms per hour most of the way in the crows nest pass (hilly mountains). We were house hunting and stopped in every town on the way. It was a 600 km round trip and I still got a 1/4 tank left. Mind you the bottom quarter is smaller than the top but the milage is VERY GOOD now! A new o2 sensor is on the way just in case. Not bad for an AWD I would say ( .)(. )
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Wow, thats a big improvement. Congrats on finding the problem and fixing it. If only it was that easy to get better economy on our Blazer :(
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Yes a big improvement indeed. Works out to about 22 miles per gallon. My first tank 3 months ago was about 8 or ten miles per gallon. I think spec is 18 on the hiway for these rigs or does anyone know what dealer specs are. I cant wait four our first 40 below to see if it starts. I hate plugging in.
Phillip Schmid wrote:

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for the passenger vans.
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Phillip Schmid wrote:

Thanks. Mine is the eight passenger AWD so I guess I am doing allright then. I filled up today and did the exact calculations and got a number of 20 mpg CDN gallon. I took the rear seats out to make room for a very big dog that reduced the weght some what. I did have the dog and the wife with me and I was driving hard so all in all I gues I am done fixing.
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