I need help with error code PO305
 

I got a 99 150 4.2 V6 249,102 miles well maintained. It's showing error code PO305. I've replaced plugs, wires, coil pack, EGR, PCV and fuel filter. I'm at a loss. I burn good fuel, use injector cleaner every 2nd or 3rd tank and most of my miles are on the highway. The only thing I can figure is the injectors. The first time I had the error code checked it showed 1 and 3 misfiring. Now it's #5 only. It only stumbles at LOW RPM too. Now also the last two years or so the catalytic converter has been making a rattling sound but I think it's the ceramic inside. I WOULD TRUELY APPRICIATE ANY SUGGESTIONS!!
Tommy

Wow High Mileage, could be anything I would start with a compression check of cylinder 5, if ok possible injector,, Good luck

Yea it is, I'm going to try for 1,000,000 miles. I didn't think I would ever own a V-6 PU but it's a damn good one. I kinda think it's an injector too but I'm not smart enough to change or check it, I don't think. It would kill me to have too PAY somebody to work my truck too.
Thanks

Well swap injectors on 5 and 6 and see if it changes the misfire cylinder. This isn't really practiced as far as I know. But I would assume you have no ways to do an injector balance test? Check the plug to see if you might have bumped it closing the gap and causing it to not spark correctly. Compression could be an issue, so if u have a compression tester you could try that. Do a cranking, idle and higher rpm check. Higher rpm's usually don't show ring blow by because the piston is moving to fast to allow it to leak.....

Thanks Wilber15!!

misfit9, this may help, may not. I have a 2000 F150 4.6L that i just got fixed...same type problem. Mine ended up being a couple broken wires in the wiring harness to the injectors. The only way i found this is i ran a "datastream" test on my truck with my diagonostic center. I had a fault on that injestor. The best way to test the injector to see if its bad is to go to advanced auto parts and purchase a node set to check injectors. unplug that injector and crank the truck. Insert the node and see if it blinks. If it does, then try a new injector. I bought the node pack for $20.00. This will tell you alot. Good luck!

forgot to add this: insert the node into the connector that you unplugged from the injector. You can also use a long screwdriver to listen for a loud....LOUD clicking sound coming from the injector. You may hear a clicking sound from the other injectors....it will be kind of soft. This is sound that is being transfered down the fuel rail. You will know if the injector is working when you listen to it and reference it to a couple of others. You can slick on the link below and find what pin number on the PCM controls the grounding for the injector, if the node does not light.

http://fordfuelinjection.com/index.php?p=88

This is for a 4.6, but i think the pin numbers are the same for both cars and trucks.

again, good luck

yup, loud tick is bad injector. If you get nothing... buy the appropriate noid light, plug it in, if it blinks you have good wiring, bad injector. No blinking- bad wiring. My money is on the bad injector, it happens. No idea on how to change injectors either.
As long as you have about oh 110 PSI minimum you're ok. I bet your truck has more like 120-125 PSI (each) at the least, if you do a compression test.

Thanks
 

Thanks Guys, I really appriciate the input.

I have 256000km on my 4.2l and it still runs like a top !!
Frank

wow
 

I thought i had a lot of miles on mine. I'm going to try to keep it and go for a million, if it don't start to nickel and dime me to the poor house. Does or has you catalytic converter rattled. Mine has been for a couple of years now. The fuel mileage and performance is good but the rattling has begun to get on my last nerve.

Thanks Frank!!

mine is still all original. the only exhaust work i have had done to mine was to take the Y pipe out and run a dual in/dual out flowmaster. and thats it. cats are all still original. Ya got to love these trucks!!!

I really do. When this design we are calling now the Heritage came out I didn't like it much kinda like the NOW F-150. My POP bought a 04 Lariat with all the bells and whistles, and I declare I like mine better. It rides, handles and gets MUCH better fuel mileage. His has the 5.4 and I know it's the difference but I don't pull ANYTHING, just air. I can get 25 on the road all day long. The best he can do is about 18.5.
Thanks for the help!!!

thats pretty good. My 97 is an extended cab, long wheel base. It has the full 8 foot bed on it. it has a 30 gallon fuel tank, and i can go almost 670 miles on the open road with it before I have to stop for gas. I LOVE that larger fuel tank. My parents live like 640 miles from me, and I can stop and fill up just before I get on the interstate, and the low fuel light will come on as I'm heading to get gas the next day. I am planning on driving mine for another 10 years. I love the ride of that ext. cab, long bed. I just love my old truck. Best money I ever spent.

Mine is a 99 ext cab short bed with the 25 gal tank. Did Ford offer the 30 gal tank in 97 or did you add it? Yours is a V-8 though, right??!! Mine is the V-6 and all they offered in 99 was the 25 gal. Yea if mine quite for good today it has been the best one I have ever had. I have had Rangers, Big Bronco's and little Bronco's and the F-150's all my life. I'm 41yo and the only car I've ever had was a 67 Fairlane. It was my first ride. DAMN I wish I still had it. It came with a 289, 3 speed on the column and I lucked out and found a 66 cross bolt side oiler 427 and stuffed in it and MAN MAN what a ride it was. It's a wonder I ain't dead.