2000 Toyota 4Runner running ruff

Tiny
TDETWILE
  • MEMBER
  • 2000 TOYOTA 4RUNNER
  • 106,000 MILES
3.4L V6. Engine light came on, got codes to change coolant sensor and proximal O2 sensor. Changed both, engine light off now. Continues to run ruff, especially when it warms. Changed plugs and plug wires with no change. Tried Fuel additives and higher octane fuel for the heck of it. Possible coolant sensor still bad? Any ideas?
Thursday, August 29th, 2013 AT 5:20 PM

9 Replies

Tiny
SATURNTECH9
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So do you have any codes now? Have you checked for new codes?
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Thursday, August 29th, 2013 AT 5:25 PM
Tiny
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No new codes.
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Thursday, August 29th, 2013 AT 5:37 PM
Tiny
SATURNTECH9
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So it ran rough before you changed everything? Does it only run rough at idle or all the time thru out the rpms?
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Thursday, August 29th, 2013 AT 5:40 PM
Tiny
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Looking for other ideas online. Going to check MAF sensor. Will take any thoughts you may have though.
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Thursday, August 29th, 2013 AT 5:41 PM
Tiny
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You can try cleaning the mass air flow sensor with mass air flow sensor cleaner. To see If it runs any better.
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Thursday, August 29th, 2013 AT 5:44 PM
Tiny
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Ran great before cooling sensor went bad. Idle tends to very from 1000rpm, drops couple 100 rpm, back to 1000rpm. Driving at cruising speed rpm doesn't change much. But it feels like misses (hesitates).
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Thursday, August 29th, 2013 AT 5:48 PM
Tiny
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If it has a rough idle have you checked for vacuum leaks?So with the old coolant sensor it fans the same s as with the new one.
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Thursday, August 29th, 2013 AT 6:12 PM
Tiny
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No vacuum leaks. I checked. It doesn't miss (hesitate) as bad as it did prior to changing the sensors, but it is very similar. It's at least drivable now. Wish I could explain it better. You know when you hear something rub occasionally or out of balance rub. That's how it it runs. If I sit in the driveway in neutral, and get the rpms up to 2000,3000 rpm and keep it there. That's almost what it mimics. Runs good with hesitation (only a few seconds). That's how it continues to run at cruising speed. I can shift down, gun it, seems to take off fine. Maybe an occ miss, but not usually. Like I said before, seems to get worse when it warms up. It even idles and runs fine the first several minutes I start it. Hopefully that helps. Or I just confused the heck out of you.
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Thursday, August 29th, 2013 AT 7:40 PM
Tiny
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How did you look for vacuum leaks which method did you use?
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Thursday, August 29th, 2013 AT 7:49 PM

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