I tested the fuel pressure while idling and it tested at 52 psi. Is this a acceptable range? I'm also getting the P0300 code. I changed the plugs, checked the wires,? changed the fuel filter, and I have good spark to all cylinders. P0300 is the only code I'm getting and runs like ****. I was thinking it could be the converter too but I removed the? censor before the converter to relieve pressure (if any) to see if it ran better but there was no change still ran like **** and no power. Don't know if that's a good way to check the converter or not.
The P0300 code means that a cylinder(s) is misfiring or is randomly misfiring. Start by checking for intake leaks, intake gaskets are common caused of multi-cylinder misfiring. If no leaks are found the next step is to replace the spark plugs. If the problem persists more tests needs to be done to diagnose problem.
IMO - 52 psi is probably fine. I'd look elsewhere. Here's a possible helpful link:
http://repairpal.com/OBD-II-Code-P0300
Definition of Diagnostic Trouble Code P0300 Category: Powertrain Definition: Random/Multiple Cylinder Misfire Detected
SOURCE: 2000 Pontiac Grand AM trouble code P0300
Im surprised that didn't fix it. On the Quad4 engine its usually a cracked coil housing.
Have you checked:
The crankshaft position system variation compensating values are stored in the PCM non-volatile memory after a learn procedure has been performed. If the actual crankshaft position system variation is not within the crankshaft position system variation compensating values stored in the PCM, DTC P0300 may set.
SOURCE: 2002 grand prix
It was the Cat. Converter on mine, Don't drive it like that too long as it will send exhaust back through the EGR Valve and burn a hole in the Intake Plenum....
SOURCE: Hi, my name is Alan,I have a 1990 Pontiac Grand
If the car ran good before you put that sea foam in the tank, there's your problem. I haven't heard one good report about that junk, some swear by it, I've always used that techron injection cleaner, and never had any complaints.
SOURCE: 1997 grand prix very ruff idle no power changed
Rough idle and no power, it could be the mass air flow sensor, or even an intake leak (vacuum). Either one I would not put passed an engine of its age. I hope this helps point you in a helpful direction. Let me know how it goes and which motor you have as well.
SOURCE: I have a 97 Pontiac Bonneville. The engine will
The fuel pump and o2 sensors both, needs to be replaced.----------To confirm the fuel pump issue try this.spray starter fluid on the throttle body and see if car starts and runs fine with starter fluid sprayed.Then it indicates fuel pump is faulty.--- Do this test when you face this stalling and no start problem.-If the engine runs smooth with starter fluid sprayed, then its faulty fuel pump and filter.The filter is already replaced, so get the fuel pump replaced too.--------Also if possible get the fuel pressure checked.This will also help.----------The o2 sensors are before and after catalytic converter.-------Both the sensors are to be replaced.------ And as per you mentioned your problem, its quite possible that faulty o2 sensor will cause this problem.------ O2 sensor is the part which sends signal to ECM( the cars computer).It sends signal to computer about fuel / air mixture.How and when to send fuel to engine.--------- If o2 sends stops sending signal to cars computer then it will not send the fuel to engine.------- In your case the o2 sensor is getting overheated and this is stopping the o2 sensor from sending signal to ECM.But when your car shuts off the sensor gets cool and again it tarts working.------ So as per problem, get both the o2 sensors checked and replaced.---------- Also get the crank sensor checked.------------
The cylinder misfire occurs due to few possibilities.There are few possible parts that are to be checked.The possibilities are as follows:-- 1) Faulty spark plugs or wires. 2)Faulty coil (pack).3) Faulty oxygen sensor(s).4) Faulty fuel injector(s). 5) Burned exhaust valve. 6) Faulty catalytic converter(s). 7) Stuck/blocked EGR valve / passages. 8) Faulty camshaft position sensor. if all the above mentioned parts checked out ok or already replaced and still the same error code shows up and same problem is noticed then its faulty ECu/ECM( electronic control module/unit).Also known as cars computer. -------------- If you notice symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs also check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. Also if the faulty fuel injectors are dirty / clogged or cracked they will block the flow of fuel and causes misfire. Random misfires that jump around from one cylinder to other. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or un-metered air getting past the airflow sensor, or an EGR valve that is stuck open.--- ---------- Getting this possibilities checked,will confirm the fault.This should help.Thanks.,Helpmech.
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