Rough idle and low RPM

[jodycochran]

2002 Mazda Protege5 200k miles.


Recently replaced the manifold catalytic converter, 2 oxygen sensors, plugs + wires and an evap purge solenoid. The car was running great for a few days, and now it dies at every stop sign. I have to keep on the gas. I have paid multiple shops to diagnose the issue. One garage thought it could be back pressure from the exhaust, causing it to stall. I took it to a muffler shop they said the pressure was within range. 3lbs is that normal? The other garage said it should be closer to 1lb.

I really appreciate the knowledge here in the forum, I have been searching through similar issues, and recommendations. If anyone has any troubleshooting tips I would appreciate it.

 

[The_big_dill]

When you say idle, the first thing that pops into my head is the Idle Air control valve, try cleaning it if you haven't yet and go from there.

 

[MaxPower]

Does it stall only when the engine is warm or when it's cold, also? Is the idle rough on start-up?

Torn intake accordion tube and EGR are common problems causing stalling/rough idling on the P5.

 

[jodycochran]

Thank you. I will look at those.

I notice it more once it has warmed up. The mechanic ordered a Fuel Pressure Regulator attempting to solve this. I have not cleaned the IAC valve yet. or replaced the EGR.

 

[jodycochran]

The Egr was the culprit. There was a price of metal lodged in the valve. Removed it, cleaned it up. Now it runs great! And passed inspection.

 

[rit14623]

The Egr was the culprit. There was a price of metal lodged in the valve. Removed it, cleaned it up. Now it runs great! And passed inspection.

Same thing happened to me. I don't even know where the metal came from. It was a thin metal piece of an oval/moon shape. I don't know what it could have broken off of.

 

[jodycochran]

The rough idle came back last week. So bad I got the random misfire cel. Pulled the Egr and another peice if metal was in there! They thought it may be from my manifold cat falling apart. I don't think that is it. Does anyone have any other suggestions?

 

[RensoreK]

Can you describe the metal? Is it part of the aluminum seal that goes behind the EGR or is it something coming from inside the valve? Have your gotten your codes read recently? Idle can be a few things I've slowly learned here.

 

[MaxPower]

Very strange. The metal must be coming from the cat, not sure where else it could originate from. It's probably not from the EGR itself. Do you have a picture?