I've got a 1990 4runner 3.slow. suddenly I've got a huge loss of power it will barely do 70 on the freeway. I'm getting about 12mpg and its got an idle around 400rpm and a rumble. Have no idea where to start. Help please
loss of power, low idle, horrible gas mileage help!
- Thread starter NavyMA57
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Check the trouble codes and let us know what it says.
Troublcodes.net Trouble Codes OBD & OBD2 Trouble Codes and Technical info & Tool Store. By BAT Auto Technical
Troublcodes.net Trouble Codes OBD & OBD2 Trouble Codes and Technical info & Tool Store. By BAT Auto Technical
First, the FSM: 1990 to 1995 Toyota 4Runner OEM Repair and Wiring Manuals Look for the troubleshooting sections.
Rough running, how so?
How does the exhaust smell when the engine is cold? If it smells like gas, then it could be not firing on a cylinder of two. Check the spark plugs, wires and rest of the ignition system. Note: You will only be able to smell gas in the exhaust before the catalytic converter gets heated up and starts working.
Valve timing may be off, the timing belt may have skipped a tooth or two on one side.
EGR system failures can also cause rough running. To much exhaust gas recirculation and you could also get unburnt gas and poor fuel mileage.
Check the catalytic converter to see if it is plugged up. The rumble tells me this may not be so.
Rough running, how so?
How does the exhaust smell when the engine is cold? If it smells like gas, then it could be not firing on a cylinder of two. Check the spark plugs, wires and rest of the ignition system. Note: You will only be able to smell gas in the exhaust before the catalytic converter gets heated up and starts working.
Valve timing may be off, the timing belt may have skipped a tooth or two on one side.
EGR system failures can also cause rough running. To much exhaust gas recirculation and you could also get unburnt gas and poor fuel mileage.
Check the catalytic converter to see if it is plugged up. The rumble tells me this may not be so.
Basics
Before you start checking all components please find yourself a good working vacuum gauge and see what the gauge tells you and go from there.it will tell you if the problem is mechanical or something else then go check all the basic components like plugs,dist cap,rotor etc. its so easy to jump the gun and start replace things that may not repair the problem. just my suggestion.
John
Before you start checking all components please find yourself a good working vacuum gauge and see what the gauge tells you and go from there.it will tell you if the problem is mechanical or something else then go check all the basic components like plugs,dist cap,rotor etc. its so easy to jump the gun and start replace things that may not repair the problem. just my suggestion.
John
Thats right, viper.
however besides all of that I would advise you to inspect the fuel system.
check pressure and flow, ie; new fuel filter and use a gauge to test for pressure via banjo bolt
however besides all of that I would advise you to inspect the fuel system.
check pressure and flow, ie; new fuel filter and use a gauge to test for pressure via banjo bolt