History: 84 westy loses power while driving-top = speed 60 if lucky, idled rough, poor mpg(-all intermitently and symptoms would = temporarily resolve by turning off key). Numerous new parts, AFM cleaning, = etc. Exhaust is all new last year with no cat.

Hypothesis: This condition will not rear it's ugly = head if I disconnect the o2 sensor. My power will stay within normal limits = and my mpg will greatly improve. Why? I don't know but the van seemed to run = better when it was dc'd, so I ordered a new one. Once the correct new o2 = sensor was properly installed, the syndrome returned.

Test: (140 mile round-trip to work) The test this = week consisted of driving to work once with the sensor connected, then = refueling and driving the same road with the o2 sensor dc'd.

One may assume that the van performed better with = the o2 sensor properly connected. Read on!!!

With the NEW o2 sensor connected, the van would lose = power every 10-20 miles to the point where it would pass nobody, it refused to = go faster than 60 mph on level highway, 45-50 on a mild incline and this is = with the accelerater floored. I stopped three times to temporarily = breathe some power back into the beast(by shutting her off), but my average speed = overall was about 60 mph. Idle at stop was crap- one foot on the brake, one on = the gas.

With the sensor dc'd, I NEVER ONCE LOST POWER = IN 3 TRIPS OF 140 MILES EACH. Further, it idled nice and smooth at a stop, and my average speed was about 72 mph!

This van has NEVER gone the 140 miles without the = power loss occurring. Now that the o2 sensor is dc'd, she made it three = consecutive trips flawlessly! Coincidence? Not a chance!

Conclusion: Disconnecting the o2 sensor cured 2 = of 3 problems; namely the power loss and the rough idle. It did NOT = drastically improve mpg as expected.

Notes: D/C ing the o2 sensor made a HUGE improvement = in the driveability of the vanagon. I liken it to the difference in = driving an old splitty verses a modern machine. The 02 sensor gives the van = that vintage feel of no power and the constant hope for a downhill grade or a = slow semi-truck to draft. It's kinda embarrassing and I think people = snicker at the slow van.

I made every attempt to minimize variables and limit = it only to dc ing the o2 sensor ie same fuel, same road, same = everything.

The decrease in mpg with the sensor disconnected is = misleading since I was able to go 72 mph(13.57 mpg) verses 60 mph(14.46 = mpg). At less then 1 mpg difference, I think the fuel economy is actually better = with the sensor dc'd, but I can test that later.

I was truly hoping the fuel economy would improve by = dc ing the o2 sensor. I'd like to know what is "average" for a 84 = westy. Average-as in across the board if you toss out the 10 % that are = excessively high and the 10% that are excessively low.

End result in mpg testing is that when my family = goes to Florida next week, we have to take the 97 Suburban now because the mpg = is better...(wife giving her victory snicker in background).

Question: If the o2 sensor gives the ecu feedback = and (yadda yadda) gives you the best mpg, AND I am comfortable with the very = minimal mpg loss with it dc'd, can I run without it forever without hurting anything = since it drastically improves the driveability as above???