94 cad eldorado

94 eldorado cad 90,000 . CHECK ENGINE LIGHT, Went off and works ok again. It has surged and stoped off and on months. Always starts right bach up. First time for a message,

CHECK ENGINE SOON IS COMPLETE MEESAGE

That CEL (check engine light) is just a kid in class waving her hand trying to get you attention because she has the answer. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code (like P0123) not just their translation into English and post it back here. 

Regarding warning lights:

  1. if the coolant temp light comes on, shut off the engine ASAP

  2. if the oil warning light comes on, shut off the engine ASAP

  3. if a FLASHING MIL/CEL comes on, shut off the engine ASAP

    ASAP means driving to the berm of the highway right now and not waiting for the next exit.

But if the MIL/CEL is not flashing, then it’s not an urgent indicator.

The auto parts stores can’t read 1994 model year vehicles. You can have a mechanic read the code that goes with the check engine light; or, you can get a GM code reader; or, you can follow the following instructions: http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c15280252cae
Check out the items in this menu: http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c15280252cae

the CHECK ENGINE SOON goes out and leaves no codes. it only blinks on when car surges and stops. it does not happen with cruise control engaged above 26 mph. weird thing to find . runs perfect at higher speeds.

Let’s see if it’s an unstable idle air control valve. Disconnect the electrical connector from the idle air control valve. http://www.autozone.com/R,2073415/vehicleId,1954001/initialAction,partProductDetail/store,1140/partType,01798/shopping/partProductDetail.htm and test drive the car. Results?