1993 Mazda 626 Rough Idle

  • 1993 MAZDA 626
  • 4 CYL
  • FWD
  • 87,500 MILES
Hi, I have 4 issues:
1- I'm having a rough idle even with the specs. RPM's (700). Worst is when I turn on the A/C, RPM's drops to about 450 and it does too when I turn the power steering all the way left or right. I'm thinking in a bad IAC or ISC valve.
2- Another thing is that my car always has the HOLD light blinking, I though I could be an Automatic Transmission problem.
3- I see that the temperature indicator in the dash does never reach the middle, like before, and the vehicle is spending more fuel, so it could be a bad thermostat or CTS?
4- The MIL light comes on like once in a month and turns off itself after I turn off the car and does not appears for another month or something.
Please I need help. I've visited a lot of technicians and nobody can do something.
Do you
have the same problem?
Friday, January 30th, 2009 AT 12:30 PM

1 Reply

Hi Irving ,

Thank you for the donation.

Item # 1.
There are many possibilities concerning this and it could be related to the CEL so we shall go to Item # 4 and see what we get before getting back to this if necessary.

Item # 2
Self -diagnostic system is integrated in PCMT and diagnoses faulty sensors (input devices), solenoid valves (output devices) and transaxle operation. Fault codes stored in PCMT identify specific components.

Codes may be retrieved from PCMT by using HOLD indicator light, OEM tester or aftermarket scan tester. See appropriate procedure.

NOTE: If retreiving fault codes using an aftermarket scan tester, follow scan tester manufacturer's instructions.

HOLD Indicator Light Procedure
1. Preferred method or retrieving codes is using special tester connected to data link. If special tester is not available, locate Data Link Connector (DLC) on left side of engine compartment. Ground service connector test terminal (TEN for 2.0L, TAT for 2.5L) and turn ignition on.


Transmission warning codes are flashed on HOLD indicator light on dash. Codes are flashed in numerical order if more than one code is present.
2. Note fault code numbers.

Item # 3
Temperature reading if it is constant, then there is nothing to worry about as the sending unit or gauge might have settled and is showing the correct reading.

Item # 4
This could be related to Item # 1 and you can retrieve the DTC by the following.

Trouble Code Access
1. Use Self-Diagnostic Checker (49 H018 9A1) and System Selector (49 B019 9A0) to retrieve trouble codes. Connect one lead of self-diagnostic checker to ground and the other to system selector. See Fig. 1 . Connect system selector to data link connector. Connector is located near battery. If system selector is not available, connect a jumper wire between data link connector terminals TEN and GND.


2. With ignition on and engine stopped, observe Malfunction Indicator Light (MIL). Note trouble codes. Check TROUBLE CODE IDENTIFICATION chart for possible cause. See CODE CHARTS for test procedures. If light remains on continuously, MIL circuit is grounded or PCME is defective.

Memorized vs. Non-Memorized Codes
Some sensor or circuit failures are stored in PCME and are referred to as memorized codes. While other circuit failures, called non-memorized codes, are not stored. Non-memorized codes can be retrieved if ignition is not turned off before accessing codes.

NOTE: To access non-memorized trouble codes, DO NOT stop engine. Connect jumper wire across data link connector terminals TEN and GND. Observe MIL and note trouble codes.
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Saturday, January 31st, 2009 AT 11:04 AM

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