Need help with rough-running 1998 4Runner
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Need help with rough-running 1998 4Runner
I'm hoping someone can help me with my rough-running 4Runner. It only has 65K miles but has been idling poorly for the past 6 months. It's almost like it is missing and seems to run worse on humid days. I've replaced the plugs, plug wires, O2 sensor, fuel filter, air filter and have even done the Sea Foam shock treatment through a vacuum line. It is still running poorly. Does anyone have any ideas? I'm beginning to wonder if I have a bad fuel injector(s).
Please help!
Please help!
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I don't believe there are any codes, but I haven't checked. I figured it would throw a CEL if it was throwing codes.
As far as plugs go, I pulled stock plugs out and put stock (Denso) back in.
As far as plugs go, I pulled stock plugs out and put stock (Denso) back in.
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#9
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based on what you wrote:
- you have not changed out your pcv. read midiwall's most recent thread on changing that out
- if you did the seafoam last, you've probably fouled up your plugs and 02 sensors. that is why most people (or those people willing to read through pages and pages of threads) either swap in some dirty plugs and 02s, or do the seafoam at a time/mileage interval where they will change the plugs/02s right after the seafoam
bob
- you have not changed out your pcv. read midiwall's most recent thread on changing that out
- if you did the seafoam last, you've probably fouled up your plugs and 02 sensors. that is why most people (or those people willing to read through pages and pages of threads) either swap in some dirty plugs and 02s, or do the seafoam at a time/mileage interval where they will change the plugs/02s right after the seafoam
bob
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I'm sorry I didn't mention it earlier, but I have changed the PCV valve. Also, I did the Seafoam treatment with the old plugs and O2 sensor in place because I didn't want to risk 'coating' the new plugs and sensor.
To be clear, here is the order of work performed to date:
1. Seafoam treatment
2. Checked all vacuum lines for leaks
3. Replaced PCV valve
4. MAF sensor cleaning
5. Throttle-body cleaning
6. Replaced Air filter
7. Replaced spark plugs and wires
8. Replaced fuel filter
9. Replaced O2 sensor
To be clear, here is the order of work performed to date:
1. Seafoam treatment
2. Checked all vacuum lines for leaks
3. Replaced PCV valve
4. MAF sensor cleaning
5. Throttle-body cleaning
6. Replaced Air filter
7. Replaced spark plugs and wires
8. Replaced fuel filter
9. Replaced O2 sensor
#14
Shot in the dark here, but have you made sure that no "new" air is getting into the system post "sniffer" (MAFS) by checking the intake tube and all its silencers, etc.? Another possibility is an exhaust leak, but generally speaking you get a loss of power with that.
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Maf
Have you tried to reset the EFI or ECU. I read on the other day that when you clean your MAF its a good idea to Unplug the fuses to the EFI and the one that controls your MAF. Might be worth a try.
Tommy
Tommy
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The only time mine idles really rough at idle is if I have a vacuum leak. Check all your connections from the intake tube.
FWIW, the most common vacuum leak I experience is the small hose that attaches to the back of the power steering pump.
FWIW, the most common vacuum leak I experience is the small hose that attaches to the back of the power steering pump.
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