98 Mazda 626 Gas, Spark Plug, Idle Issues

**Manual 1998 Mazda 626 4cyl** Wow this car has caused me many problems.. I would appreciate if I can recieve some advice concerning the certain issue the car is going through. Well here is the breakdown.. the timing belt is new, coil, fuel pump and a number of clean outs such as fuel injection cleaning and radiator flushed out. So the issues now are #1 car hesitates to start up so u need to press on the gas to help it turn on #2 "3" spark plugs were filled with fuel and the other one had carbon deposits on it. So i took it to an authorized Mazda Dealership and this is what the diagnostic came up with.


==Codes P0301 and P0420 in system
#1 Cyl misfire and IAC valve duty cycle higher than expected. Needs new fuel filter hose from filter to fuel rail. Needs Pre-Cat replaced due to efiiciency below spec. Needs new idle air control valve. Also needs new drive belts.==


So these are the results from the diagnostics but came to a high cost to fix. The mechanic had told me that if the problem still continues than there could be a problem with the PCM. If someone could confirm with me that these issues fixed could solve the problem or if someone has had the same problem I would appreciate your help.

if any one needs an IAC valve for a 1998 Mazda 626 4 cylinder, I have one for $400. Brand new.

Start with the Idle Air Control valve - a white plastic cylinder (2.5"dia X 4" approx) under the inlet manifold - diaphram wears out. In Oz you cant buy them for the older Fords or Mazdas so I removed it and blocked the pipe using a bolt and a pipe clamp. Working well (12 months later).

Yes.. Either replace the IAC valve or block it off like RicW said. You might be able to go to a jucnk yard and get one cheap.

**Manual 1998 Mazda 626 4cyl** Wow this car has caused me many problems.. I would appreciate if I can recieve some advice concerning the certain issue the car is going through. Well here is the breakdown.. the timing belt is new, coil, fuel pump and a number of clean outs such as fuel injection cleaning and radiator flushed out. So the issues now are #1 car hesitates to start up so u need to press on the gas to help it turn on #2 "3" spark plugs were filled with fuel and the other one had carbon deposits on it. So i took it to an authorized Mazda Dealership and this is what the diagnostic came up with.


==Codes P0301 and P0420 in system
#1 Cyl misfire and IAC valve duty cycle higher than expected. Needs new fuel filter hose from filter to fuel rail. Needs Pre-Cat replaced due to efiiciency below spec. Needs new idle air control valve. Also needs new drive belts.==


So these are the results from the diagnostics but came to a high cost to fix. The mechanic had told me that if the problem still continues than there could be a problem with the PCM. If someone could confirm with me that these issues fixed could solve the problem or if someone has had the same problem I would appreciate your help.

i did two things to fix my idle problem. What fixed mine was changing the rubber adapter (the spark plug end of the spark plug wire) that fits onto the plugs. It might be better replacing the wires with a dealer grade. I used an autozone grade, and i don't think that quite did the job.

Part Stores offer many grades. You just have to keep on telling them that is what you want. I always go for the lifetime warrenty, just to be safe.