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Discussion Starter #1
2007 eclipse gs 2.4. 188k The car is hard to start , misfiring rpms fluctuating. I can baby the gas and after about 4 minutes will settle out then It will run and start good all day till the next morning I have replace many parts , it keeps throwing p421 p431 codes. I have replaced all o2 sensors coils, spark plugs, coolant temp sensor ,maf new timing belt and sensor Could my cat be causing this?
 

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For sure, especially at that mileage

I would advise not to keep running the engine with them clogged up, it's very bad for the engine to have all that backpressure with nowhere to go, the cats can even break up and get sucked back into the engine, then you'll have major problems

Take the header off and get a crow bar
 

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Discussion Starter #3
Thank you, I will take it off this weekend. Will the o2 sensors read ok and everything run fine being gutted?
 

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Thank you, I will take it off this weekend. Will the o2 sensors read ok and everything run fine being gutted?
You'll still have the same cat codes, because without cats the ECU will think that they are bad and passing too much exhaust, but at least you won't damage or blow up your engine from a clogged exhaust
O2 sensor spacers (spark plug anti foulers) can work intermittently to keep the codes away, otherwise the Fastworks tune is required to trick the ECU not to pop those codes anymore
 

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I took cats off and gutted them one side had already started to collapse. Got it all back together and after driving it about 40 miles it runs fine

Got up this morning and it still very hard to start, sputtering and spitting. You have to try 5 or six times feathering the gas. I finally let it sit with key in on position but not running and it started better

Do these cars have fuel pressure regulators? The fuel pump was changed a few months ago trying to fix this problem. If it sits overnight it is hard to get it running, once you do it’s good all day.
 

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I took cats off and gutted them one side had already started to collapse. Got it all back together and after driving it about 40 miles it runs fine

Got up this morning and it still very hard to start, sputtering and spitting. You have to try 5 or six times feathering the gas. I finally let it sit with key in on position but not running and it started better

Do these cars have fuel pressure regulators? The fuel pump was changed a few months ago trying to fix this problem. If it sits overnight it is hard to get it running, once you do it’s good all day.
I believe the pressure regulator is just apart of the whole fuel pump assembly with the pump under the rear seat
 

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Discussion Starter #7
New fuel pump two months ago, it’s like the fuel pressure leaking down overnight. Bad injectors. O rings.
 

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Discussion Starter #8
if I was to spray starting fluid it it stars right up that would be indicate a fuel pressure problem right ?
 

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if I was to spray starting fluid it it stars right up that would be indicate a fuel pressure problem right ?
Yeah probably
It’s not recommended to spray starting fluid on a fuel injected car
You might have leaky injectors

the problem is that this car doesn’t prime the fuel pump prior to engine cranking, it only starts pumping the fuel pump once the engine is cranking

my WRX will prime up the fuel pump for a few seconds right when you turn the key on
 

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Discussion Starter #10
Im going to buy some injectors, what do you recommend and where ? I have been buying parts from rock auto , also what about a bad egr? Would this cause this extreme hard start in the morning?
 
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