Originally Posted by
manlaw38
I have a question. I replaced all my spark plugs with factory plugs and new wires and new coils and new RCM and rebuilt Bosch injectors and still my car throws codes and runs rough . I reset the check engine light it runs alittle better then it starts to run rough again. its gotta be something simple . I drove it all day today and once I started to get aggressive with shifting 6 speed , it started to act up. I will try tomorrow to see what will happen once it cools down. Only thing I can think it can be is the fuel pump. the scanner said #1 cyl was miss firing then it said it was #5 and # 6 was misfiring. it was running great until today. Does anyone have any ideas?
Thanks
I'm rather amazed you replaced even the COIL PACKS and injectors without measuring the fuel pressure. Did you really do that?
In the last year, I have replaced the pump in the Crossfire (2007, 62,000 ,miles) and my 2005 Ranger (129,000 miles) - the pump/filter/regulator must maintain 55-60psi and after so many years and miles, what are the chances they are failing? A pressure any lower than 45 will make a BIG difference. My Ranger can't idle below 22psi and stalls at such pressure if you press the pedal (ask me how I know, I played with it a lot before taking it to the garage.
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Harbor Freight, Summit Racing, Amazon and many local parts stores sell easy to use fuel pressure test kits for $30 to $50 that make fuel pressure tests almost as easy as measuring your tire pressure. I certainly would not have gone to all that trouble before knowing the fuel pressure.
I bought this one at SUmmit Racing back in 2018 for $32 (Amazon is NOT the lowest price any more than WalMart is) - it made it easy to know why my Ford Ranger was acting up - bad pump. I've put it on the Crossfire, but only to play with it, not cause the car was acting up. (Got a reading of 58psi).
Don't throw parts at something until you have done the easy, cheap tests. And Im sure a LOT more fuel pumps have died on our cars than coil packs. (Altho I commend you for changing wires with plugs, people who change plugs but leave the old wires REALLY should not be allowed near tools.)