Disconnect the battery for about 10 mins first to see if it is not just a computer reset that is needed.

Can you check intake vaccum ? Should be 16-22 inch Hg at idle. If the vaccum is low, could be a clog in the exhaust, most likely the catalytic converter.

Also you can measure the current at the EHA. If you just have the ignition switch in run position, there should be between 10-20 ma thru the EHA. At idle the current will be lower. Now if you blip the accelerator, you should get greater than 15 ma thru the EHA. Note that the current must be measured in a series circuit not in a parallel circuit like measuring voltage. This test should be performed when the car is cold.

Does your car have a EGR valve ? Check the valve and the vaccum that operates the valve. At idle, the vaccum that controls this valve should be less than 2 inch Hg, i.e. the valve must be closed. At about 2000 rpm, the vaccum should be between 4 and 6 inch Hg, enough to open the valve. Malfunction in this valve's operation will cause problems at idle as well as rough acceleration. Make sure the car is cold when testing this.

Check the air sensor's potentiometer. The car is off. The resistance between the center and one of the neighbouring pin should be about 1 to 2K when the plate is all the way to the top. Now if you gradually press the plate, the resistance should gradually increase, there should be no jumps greater than 2K. If it is smooth, check the voltage across the same two terminals. Now the car is on (and you have to also connect the sensor's cable back to the sensor, can use some alligator clips). At idle, the voltage is between 0.5 and 1V. Now as you gradually depress the gas pedal, the voltage should smoothly increase, there should be no erratic voltage change.

Check the coolant temp sensor also. This sensor sends engine temp info to the fuel computer (as well as the ignition computer). When the engine temp is cold (about 20 degc), the resistance should be between 2.5 and 3.5K. When the engine temp reaches 80 degC, the resistance should drop to about 250-350 ohms, a factor of 8 to 10. Check the sensor's cable, if the cables are broken, the car will go into a limp mode.

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Saumil S. Patel