octane knock

I have a 93 ranger with the 3.0l engine, 5 sp 4x4. In first and second gear it seems to have tons of power, but in third and fourth it seems to be gutless. Also if it is under any load or modest acceleration it has a very annoying consistent octane ping, which sounds like a constant rattle. I was told that the most common cause of this is a large carbon buildup in the engine and have tried higher octane fuel as well as several products that claim to remove this buildup. I was wondering what else can cause this and what to try next. Note that it passed the ontario drive clean emissions very well. Thank You

I have a 2000 3.0ltr...I have noticed the same problem...excessive ping on acceleration in the high gears. I was told that sometimes it has to do with the engine timing, and that is something that cannot be easily/cheaply corrected due to the electrical complexity. One thing that I did to, is take out the Motorcraft spark-plugs and go with the bosch plat. 4's. They are expensive, but I have noticed alot of difference. The pinging isn't completely gone, but it is much quieter.
Hope this helps.

inexpensive mod to help http://rogueperformance.com/IntakeAir.html

had the same problem on my 1999 with 3.0 and got rid of the sound...
moved up to 89 octane gas, used hi-performance fuel injector cleaner (has jet fuel in it - from STP) This may work for your ranger. If not, go with new, more performance oriented spark plugs. I wouldn't recomend messing with the timing; I talked to my neighboor who is a mazda mechanic (ranger = B series) and he drove it and said that some people had been complaining about the B3000 (3.0 L engine) making a similar noise. On some free time, he changed the timing a little bit (advanced and retarded) and it didn't make a difference.
I have been told though that advancing it a few degrees will give you a little more high end power... :cheers:

I've had the engine ping problem come up on three light trucks. Before fuel injection, the solution to carbon build up in the engine was easy. A $6 dollar bottle of "top engine cleaner" poured right down the carb worked great. It was amazing how much this improved performance. With fuel injection the solutions are not so simple. There are services out there that do internal engine cleaning, but it costs 100-200 $. I think PEP BOYS offers this service. I had it done on a 95 Mazda and it effectively took care of the ping problem. It is expensive, but if the only other solution is buying premium gas, it probably works out cheaper in the long run to have the cleaning done.

I never had much luck with the fuel additive cleaners. I don't believe they can possibly reach a concentration high enough to do much good. Several mechanics I talked to insisted that BG products are effective, but they also cost about $20 a bottle. It seems more cost effective to just have the cleaning done at 100k miles or so.

Most recently, my 2004 Ranger developed a ping problem at 5k miles. I discovered a problem with the spark plug wire routing. The factory did a pathetic job of installing the wires. For the three cylinders on the right side of the engine (opposite the distributor) the wires run thru a narrow slot between the valve cover and a wire harness. After a few months of use, the wire harness sagged and jammed the spark plug wires together. When the wires run too close, it can cause a ping problem. I installed some retainer clips on the wires and so far it seems to have solved the ping. I would say this is a design flaw on the Ranger. There need to be more engine mounted retainer clips.