Desperately seeking a solution...

[mawmaw]

We own a '92 4.0 4x4, problem is pinging and
really poor gas mileage, we're getting around
260 miles to a tankful, the vehicle has 97,000 well maintained miles on it, so far we
have changed the plugs, wires, o2 sensor, air filter, fuel system cleaner, cleaned the maf
had it put on a diagnostic computer at a garage, which wasn't cheap, and all they could say was to unplug the octane shorting block for pinging and that it's prolly getting poor gas mileage cause it's getting old, I don't buy it. Needless to say we are
at our wits end, gas is too expensive to continue on this path, please please please
could you tell me the magic cure?????? I had been reading about the thermostat cure and our truck also stays below normal on the gauge, could it be??? and as far as changing the plugs could someone tell me why after we changed them did our mileage get worse?? and yes they are gapped correctly. thanks soo much for any input, as this is our last resort, next step is dynamite up the 'ol tailpipe.

 

[Rick]

I had similar problems and replacing the catalytic converter did the trick. Impossible to tell if it will help you though.

 

[xr600boy]

I think I would have to agree with Rick on this. I have 130k on my 92 and I can get 300 on a tank. By the way my temp has allways been below normal from day one. Good luck with it.

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92EB 2wd with chip and Flowmaster catback system, and open air box.

Jim
"The older I get the faster I was."

 

[wabbit]

Rick,
Could you give me some info on a high-flow cat?
I have a Borla cat-back on the way and I would like to replace my cat before hooking it up.
p/n's,prices, and/or links would be great.
Thx
Warren

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'91 Explorer XLT 4WD

 

[Rick]

I don't have any part numbers for you. I had mine installed by a custom exahust shop here in Phoenix. They charge 150.00 including the install.

 

[FMExplorer]

Mawmaw,
I have a '93xlt 4x4 w/ 118k miles on it. I do a variety of driving - around town, highway, off-road, etc... For what it's worth, I was getting about 275 miles/tank with 235/70 Michelins on it and it dropped to about 250 miles/tank with me new 31x10.50 Mud tires. However, speedo hasn't been recalculated, so it could be a little better. Along with everything you have done, have you checked tire wear and alignment? If your alignment is just a shade off your mileage could drop by as much as 8-12%. Just a thought...

Jon M

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Jon McLeod
'93 XLT
K&N Drop-In
Modified Airbox
Kenwood Audio w/ 6-disc changer
31x10.50 Dunlop Mud Rovers
Rancho RS5000's

Next project: visit http://www.jonmcleod.com for more info!

 

[FMNavajo]

Just another thought on MPG, I noticed you've changed O2 sensor, plugs, wires and a multitude of other items. I did all this as well and it turned out to be the intake manifold gasket leaking. Check the #5 spark plug and see if it has any carbon build up, considerably more then the others. Mine had a build up on #5 and I changed the fuel pressure regulator and retorqued the lower intake manifold. The pinging stopped and my gas mililage went up a bit. I then pulled the intake off and put a new gasket on and cleaned all the parts prior to installation, they really needed it, and I was back to getting 18 - 19 in town and almost 22 on the highway, (when I drive the speed limit).

Hope this helps your dilema,
FM

 

[Pete]

As far as I know it is possible to check for a plugged catalytic converter. A small hole is drilled in the exhaust pipe just upstream and just downstream of the converter. A differential pressure gauge is used to measure the pressure drop across the cat with the engine running. If the pressure drop is higher than spec, the cat is clogged and should be replaced. There is a muffler shop here in Bakersfield that does this test so I suspect you could find one in your area also, especially one that does performance or custom exhaust work.