91 240 hard start and high idle help

Been having several issues with my 91 240 n/a auto that have slowly been getting worse. It has to crank for nearly 5 Seconds before it will start, Once it's warm it hunts for an idle and if it does settle on an idle its hi, around 1500- 1700 rpm. No codes currently and I've replaced throttle position sensor and idle air control valve, and crank pos sensor. I've also checked for vacuum leaks with none found. It does have an EGR and it seems to be working properly.

When you replaced the throttle switch did you make sure the adjustment is correct? How are the spark plugs? Is the gap correct? If you are using copper spark plugs that are more than a year old and the gas in your area has alcohol in it. Your spark plugs are bad. Make sure you set the gap on any new plug you use. .028" is what to adjust to. Make sure plug wires are in spec and cap and rotor are in good condition, too. Watch out for the coil wire shorting out.

How is the battery charge? I would check connections in the ignition system like the coil and the ignition amplifier near the battery. A high idle for a few minutes after starting is normal if it is very cold. Then it should go down to normal after a few minutes.

taylor84240harris said:

crank for nearly 5 Seconds before it will start...Once it's warm it hunts for an idle... checked for vacuum leaks.

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Manually, engage fuel pumps at fuse panel, then crank...or switch ignition on...wait for pumps to prime, then engaged starter. Firstly, fill up fuel tank first.

Unplug brake booster's vacuum line, and plug hole on intake.

High idle suggests air coming into intake...throttle plate out of adjustment? Must be set to OEM specs...no iffs, buts, or ands.