3.0 misfire at 2400rpm

[FordBoy]

hey guys i need help bad. my uncle and myself rebuilt a 1998 3L 5 speed ranger. it has a missfire at 2200, 2300, 2600 rpm in every gear only under load, it seems to be moving to a wider rpm range the more i drive it, it only has this miss fire when it's warm. no check engine light, it's still getting 28 mpg, passed an etest with this problem although it did have high noix which i dont know if there is a connection, it has 60psi fuel pressure. for various problems it;s got many new parts, tps, iac, plugs, wires, coil pack, coolent temp sensor, cleaned maf with proper cleaner. i'm stumped and my last truck had the same problem and we never figoured it out. i dont have a scan tool so i cant check codes. any suggestions are much apreciated sorry for the long post

thanks
jimmy

 

[fourwheelford]

Could be a valve, have you done a compression test? Also could be the fuel filter or the syncronizer taking a hike on you. The syncro seems to cause more problems than its worth, yet another brilliant ford design.

 

[FordBoy]

hey man thanks for the input i looked into it a bit more and it is miss firing under load or not. i pulled the codes yesterday and it has a bank 1, sensor 1, o2 sensor slow responce and bank 2, sensor 1, malfunction in heater o2 sensor and 02 sensor slow responce bank 2, sensor 1, as well as cam position malfuntion. i will change the cam position sensor, but is there a way to tell which o2 sensors i need to change? and i spoke to a mechanic and he said my cat is probably the reason some of the o2 sensors are slow. thanks for your input any more help would be much appreciated

 

[Runnin'OnEmpty]

hey man thanks for the input i looked into it a bit more and it is miss firing under load or not. i pulled the codes yesterday and it has a bank 1, sensor 1, o2 sensor slow responce and bank 2, sensor 1, malfunction in heater o2 sensor and 02 sensor slow responce bank 2, sensor 1, as well as cam position malfuntion. i will change the cam position sensor, but is there a way to tell which o2 sensors i need to change? and i spoke to a mechanic and he said my cat is probably the reason some of the o2 sensors are slow. thanks for your input any more help would be much appreciated

Fordboy, bank 1 is the passenger side bank, and bank 2 is (obviously)
driver's side. Sensor 1 is the upstream sensor, or the one nearest the
exhaust header.

Slow response usually means the sensor is getting worn out;
don't really know about a clogged cat causing that code....?

Make sure the cam position sensor code isn't caused by the synchro.
It's a common problem in the 3.0, usually coincides with a
bird chirp noise heard from underneath the passenger side wheelwell.
If the synchro goes bad, it can also take out the cam sensor......

 

[fourwheelford]

If the syncro goes bad your motor will grenade(as well as take out the sensor ) but thats the least of your worries at that point. I guess a plugged cat could cause a slow response from the o2 sensors but I don't know enough about that to give any good advice. Im with runnin on empty about them getting worn out but they are probably caked with carbon or other BS of that nature, stupid trucks have to have 3 o2 sensors that are in really crappy places, wear good gloves and plan on racking the shit out your knuckles if your doing it your self Let some PB blaster sit on them overnight that helps the little bastards come out easier. Change that Cam position sensor for sure then look into the o2 sensors, that stuff is better than a messed up valve though.

 

[Horch02]

I am new to this site and I could use some help. I have a 2000 Ranger 3.0 automatic 180000 miles. About 2 months ago I had a loud chriping, so I had the cam syncro replaced. This solved my problems up until a couple weeks ago. I have an intermittent code P0340(camshaft postion sensor), replaced sensor, still throws code. Bigger problem is that at higher RPMs i get a miss/buck. Could this be my cam syncro and assembly again? What should I do next?

 

[det107]

Did you replace the sensor on top of it ??