Code P0300

The fuel pressure was the second thing I checked after the cap and rotor. It was excellent.
Did not check the compression because the Astro van is a nightmare to work on, especially on your back on the floor. The truck ran perfectly, until whatever failed messed things up.

I am almost positive it was 65 lbs. I will pull the doghouse today and confirm. I have had no less than six fuel pumps replaced on my 1996 Astro! So I wouldn't doubt that it could have been the cause. I had to cut a hole in the floor of the truck to get faster access to the pump for replacement. Saved dropping the tank each time. The truck coughs and stumbles starting up from a stop until I give it more throttle! At higher speeds it runs fairly well until I let up on the throttle a bit, then it stumbles (misses). I hope the jpg with the fuel trim data helped. I will reply again once I pull the dog house and take another reading to the fuel pressure.
Wayne

I am glad I rechecked the fuel pressure! Turn on key, pressure goes to 65 lbs! Then immediately falls to 57-58 lbs! Book says it should be between 58-64 lbs. Would you suggest replacing the fuel pump? It is a bit messy, but if you say yes, I will cut through the floor above the tank and replace the pump! I've done it before on the 1996 and it is the best way, especially, if I have to do it again down the road.

Thank you very much,

Wayne

Just one more thing, since about ten to fifteen minutes ago when I took the readings, the fuel pressure dropped to 51lbs. With a new spider injector system installed, it must be flowing back into the tank. Your guess?

Thank you very, very, very much for your help!
Wayne

Roy,
Well, I just replaced the fuel pump on the Astrovan which was less than a pleasant experience. With the new pump, the pressure hits 63-64 lbs and then immediately goes to 58-59 lbs which is at the low end of he 58-64 lb range the manual says is OK. That is only 1 or two lbs more than the pump that was in there. Then, the pumps pressure falls to 50 lbs in about 10-15 minutes. No gas is escaping from the repair. The spider injector mechanism is new and tested for leaks during assembly. Where else could the pressure be leaking to? I am at a loss. So much money time and effort. I haven't taken it out for a test drive yet, but I would expect the same jerking and error code P0300 misfire. Any suggestions would be helpful. I don't know if you still have the info from my live data, etc.
Wayne

OK, but I have to keep the dog house off and it's cold outside!
I'll check it out.
Thanks

Could I get an accurate reading by just putting a hose on the exhaust pipe and putting that out of the garage and bringing the rpm up to 2 or 3 thousand? Or, should I take it out on the highway?

OK, I will have to do that tomorrow.
Thanks Roy

I don't see my earlier reply message here, so I'll try to remember what took place on my little test drive. At 30mph in OverDrive, the fuel pressure maintained pretty close to 58-59 lbs. As I increased speed to about 40, the pressure went up to about 60 psi and then settled back to about 58-59 lbs. Using 2nd gear and low speed (about 20 mph) the pressure went up to around 62 lbs while coughing and jerking like crazy. Then the pressure went back down to about 59 lbs when no longer accelerating. The truck is acting just like it had from the initial P0300 code and all the stuff I've replaced like: Spider Injectors, Distributor Cap and Rotor, Plugs and Wires, and now Fuel Pump. Any suggestions besides setting the truck afire!
Wayne