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So, I have recently replaced my o2's with some good working ones (used but good) and my car is still getting crappy fuel mileage, I am not impressed at all with the mileage that I am getting even though I am running pretty stoich when I am driving. Something that I noticed is that when I am sitting at a light the car will be idleing fine, then all of a sudden it will shudder a slight bit and not run as well and sometimes it will die due to flooding i am guessing. When this happens the car is running RICH, I can verify this so it is not a question. My question is why is it doing this? Is it related to the PRC soleniod at all? Does the PRC solenoid affect mileage on a jspec Millenia DE? I currently have my fpr hooked up to my IM like alot of other users do on this forum. o2 sensors?

Any help or insight would be appreciated.

Hey solo I dont know if you have a cat or not or if it has been replaced lately, but I do know if it is old/clogged up it will cause the o2's to get a inproper reading. This would cause poor gas/mileage and idle issues.

Kirk95gs wrote:Hey solo I dont know if you have a cat or not or if it has been replaced lately, but I do know if it is old/clogged up it will cause the o2's to get a inproper reading. This would cause poor gas/mileage and idle issues.

No cat man, running headers, 2.5" ss mandrel pipe, 18" straight through resonator and megan muffler

the PRC won't effec t gas mileage. i don't run it and I always got perfect gas mileage.

ya, most people just unplug the vacuum lines to the prc solenoid, and run a vacuum line directly from the intake to the FPR.

that isn't your problem. Try testing your coolant temp sensor(the green plug one on the waterneck because that tells the ecu how hot or cold the coolant is, and adds or removes fuel as needed.

I hope that helps.

7

I will test it but I have no idea what that has to do with fuel.

that sensor tells the ecu if the engine is cold. Then, if it is cold, the ECU adds fuel to help warm up the engine. If it showing more than normal resistance, the engine will run way rich.

heres a newbie ? what is the PRC?

se7en wrote:that sensor tells the ecu if the engine is cold. Then, if it is cold, the ECU adds fuel to help warm up the engine. If it showing more than normal resistance, the engine will run way rich.

That is only when it is cold though, my temp gauge from what I can see is quite accurate (for stock gauges).

MgXs3 - PRC stands for pressure regualtor controler, it helps the FPR it seems to aid in making the correct fuel pressure IIRC.

the gauge runs off a separate sensor alltogether.

there is three coolant temp sensors.(sometimes two)

If any one is not working, it will run rich.

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solo_ryder wrote:

se7en wrote:that sensor tells the ecu if the engine is cold. Then, if it is cold, the ECU adds fuel to help warm up the engine. If it showing more than normal resistance, the engine will run way rich.

That is only when it is cold though, my temp gauge from what I can see is quite accurate (for stock gauges).

MgXs3 - PRC stands for pressure regualtor controler, it helps the FPR it seems to aid in making the correct fuel pressure IIRC.