Oldsmobile Racing

oldsmobile
intrigue
engines

#1

I have a 2000 Olds Intrigue with 108,000 miles, auto transmission. The engine occasionally races. This happened for the first time a few months ago on a short trip to the grocery store. I didn’t have to touch the gas pedal the entire way to the store; even going up hill the car was accelerating. When I left the store the car drove fine.

Two other times this has happened after long trips, 250 miles. I had a mechanic look at it but as it was not racing while he drove it he didn’t know what was wrong. The mechanic took some parts apart and cleaned them (I don’t know what parts.) Regardless, my car still races occasionally.

I should also note that as of about 6 months ago I only drive the car occasionally. It used to be a daily driver and I would put on about 15000 miles a year. Now the car is riven once or twice a week and not very far.

I have a theory and was wondering if it is plausible. I think the racing might be related to the cruise control; my thinking is that the car “thinks” it is on cruise control. I came up with this theorem after a couple of long drives, during which I used cruise, which always lead to the engine racing.

Thanks for anyone and everyone’s help!


#2

For the theory to be correct you’d have to have two concurrent problems. Your car would need to think you’ve engaged the cruise control and the cruise control system would simultaneously have to be malfunctioning. I see that scenerio as a low probability.

Last week I would have suggested a possible throttle position sensor or manifold absolute pressure sensor. These both provide signals to the ECU to tell it what the engine needs are, which are then used to calculate injector pulse width. These defects should trip a fault code (CEL light ahould light).

Those are still possibilities, but now I’ll add to that checking to see if you have a “throttle by wire” system. That’s a system where pushing the accelerator sends a signal to the ECU, and it seems to be that when some corrosion and/or crud happens to some part of that component it can malfunction with exactly the symptoms you describe…and not trip a fault light. These have apparently be installed on some cars for more years than I realized.


#3

The problem might be with a defective Idle Air Control valve.

Locate IAC valve on the throttle body. Start the engine, and with the engine idling tap on the IAC valve with the handle of a screwdriver. If the idle speed changes when doing this replace the IAC valve.

Tester