[djrobnyc]

I just looked at 1995 Olds Cutlass Supreme Convertible 3.4L, with 113k at a new car dealer (he took it in on trade)

Two things I did notice in the test drive:
a) With the A/C going, upon acceleration, the A/C "dropped" out to almost shutting off, and then back under normal coasting, it came back. Is this a major problem? Is it just a timing issue? It happened a few times.
b) The fuel gauge "floated" - showed a half tank, then moved down to below a quarter, then back. It seemed to happen a few times as well, under acceleration but coasting as well.

Any answers to the above questions would be greatly appreciated. Overall, the car seemed tight - but don't want to proceed without a good idea whether these issues would be big bucks to repair. Thanks!

[rocketraider]

I think those cars have an A/C cutout switch on wide open throttle. I know some of the 80s cars had them. Reasoning is to drop the a/c compressor load under hard acceleration for max power.

These cars also have cycling clutch a/c compressors. If system is functioning normally and is charged properly, you'll hear the compressor clutch cycling on and off.

Can't help on the fuel gage diagnosis. I think it's modern gasoline formulations causing that, because I notice my 70s cars doing it sometimes.

But under hard acceleration, fuel in the tank sloshes around and may cause the sending unit float to drop and rise as fuel level moves around.

[joe_padavano]

All cars since the mid 1970s have an A/C compressor cutout at wide open throttle but ONLY at wide open throttle. The question is, what do you mean by "cuts out". The GM air conditioning systems use vacuum actuated doors to route the air to the defrost vents, dash vents, or floor vents. If there's a vacuum leak or a bad vacuum diaphragm, the vent doors will change position under low vacuum conditions - such as during acceleration. I have exactly this problem on my 86. The default position (in the absence of vacuum) sends air through the defroster vents. Drive the car again and see if the A/C switches from the dash vents to the defrost vents during acceleration (low engine vacuum) and then comes back to the dash vents after you let off the throttle (and engine vacuum is restored). This can be as simple as a vacuum check valve under the hood or as complex as ripping the dash apart to get to a bad vacuum actuator.

Of course, the real question is, why do you even care about the A/C - it's a CONVERTIBLE!!! [img]<>/grin.gif[/img]

[pfloro]

Hello djrobnyc:

The 'floating' fuel gauge indicator may be quite normal for GM cars of
this era. The fuel will slosh fore & aft within the tank when accelerating and
coasting. The 'moving coil' gauge doesn't dampen sudden changes being
'reported' by the in-tank sending unit. My '84 Toronado had done this since it was new.
The lower the level of fuel in the tank, the more pronounced the fluctuation.

As an interesting comparison, the gauges in our '66 Mustang don't exhibit this fluctuation. These gauges
(fuel, temp, oil pressure) have tiny heating elements within them. The heaters bend a heavily damped
bimetal strip which is attached to the pointers. Perhaps more primitive but more stable...

Good luck with your decision.

Paul