Hey guys I am new to the Ford community so I don't know much about Rangers. I recently picked up a 2000 Ranger with a 3.0L 4 speed Automatic with 75000 miles. The truck runs great from 0-50 but when it hits 4th gear in overdrive it starts to pre-ignite. It is only when the motor is working pretty hard (up hills). The oil pressure is good and the temp is good. There is no check engine light. I just changed the oil and air filter. I read some posts and thought it may be related to the EGR valve. I got a new pdfe sensor which seemed to be a big issue with these trucks - no change. I also tested the EGR by putting a vacuum to it - the engine died down as it is supposed to. I am not really sure what to try next. I know it must not be major because it runs great otherwise. If anyone has an idea please help me out. Thanks

 

timing

 

Sorry to say 3.0 pinging=Normal.Plugs will help for a little but always returns. 3.0 is a great motor but you will have to get use to this.

 

Ok that is cool, I am used to hondas which ping usually when the motor is overheating or the timing is off...is there a way to adjust the timing, there is no distributor right coil packs instead? Thanks for the help

 

go to your ford dealership and buy a can of PM-3 carburetor tune up cleaner. slowly ingest it into the motor through the vacuum line from the brake booster. follow the directions on the back (i think it says use 5 oz, let sit 15 mins etc) repeat this 3 times, change the plugs and oil right after (plugs after it cools, aluminum heads) and your pre-ignition will be reduced if not eliminated all together. There is an old TSB for this and it works really well

 

I had the same problem with my truck. It ran fine even after 50 when on flat road over 50 up hill the truck would buck and pop. Turned out to be the plugs and wires. Check your plugs for carbon tracking.

 

clean the MAF ,use maf clean don't damage the wires, & throttle body ,carb cleaner works, use lucas fuel conditioner / injecter clean new fuel filter maybe sea faom it to should lesen it alot till it gets really hot and humid. its the heads/ chambers causing it to happen sharp edges in the combustion chambers they cause dieseling aka pinging. the sct tunner can help some to stop it from being so previlent, plus you'll get some power / driveability.