Need diagnostic help asap!
- Thread starter djtc
- Start date
CitadelBlue
New member
I'm having P0171 code issues as well. 2002 4Runner Limited ... 4WD 142000 miles; original - plugs, wires, fuel filter, O2 sensor, gas cap and PVC Valve. Air Filter not new but seems OK. Replaced AF Sensor in 2008 due to CEL P1135. Cleaned the MAF with the CRC MAF spray. Ran better for 24 miles ... gassed up with Sunoco 87 Octane. CEL P0171 returned. Based on the above, Looks like I need to spend some money on plugs, O2 Sensor, MAF sensor, and maybe AF Sensor, PCV Valve ..... Thoughts?
CitadelBlue
New member
Cleaned the PVC valve and it appears to be working OK. I DID check the vacuum hoses and all appear OK, but it sure is a spider web of black hoses. Are there any tips of typical hose that could be cracked or loose and have fallen off? I seem to smell burning rubber at times when I shut off the engine and get out of the 4Runner? Replaced the O2 sensor and the CEL returned after 10 miles. I've got a new MAF on order.
Last edited:
It sounds to me like you still have the original issue which is most likely a vacuum leak. Another possibility is an exhaust leak and what could be causing the sound. I watched on my iPad so sound not so good.Didnt have time to go get the plug wires and change out the fuel filter but I did do the following:
-Removed and cleaned Idle control valve
-Really cleaned out the throttle body !
-Installed a new coolant temp sensor
-Switched the coilpack from cyl 3 to cyl 1.
End result... Worse idle but I don't have a multiple missfire code anymore,it's just #5 now that misssing.
-I also still have the P0171 lean code..
Plus side the truck feels even quicker now, but when I got back home my rear driver wheel started locking up when brakes were applied at low speed :bash:
The re is a loud thumping sound coming from the intake thats not audible on the video .I'm guessing its from cyl #5 missfiring.You can hear the very rough idle though!
Also after cleaning the tb, you will need to have the ecu relearn the idle settings. Just did it on our Infiniti and gmc. You will need to search for a drive cycle to do that.
Richard808
New member
I remeber another thread awhile back with similar issues. The Op of that thread replaced about everything before finding his crank sensor wasnt fully plugged in. Might be worth checking. I think he had multiple misfires and lean codes also.
CitadelBlue
New member
and where is the crank sensor located? Got a picture?
Richard808
New member
I believe its behind the crank pulley, toward the driver side of the pulley.
What is fpr?
fuel pressure regulator
CitadelBlue
New member
After cleaning the MAF with the store bought spray and then a second time with alcohol ... I purchased a new Denso 197-6020 Mass Air Flow Sensor and installed a new air filter .. I cleared the CEL and after 50 miles of driving no CEL ..... hope this was the fix .....
Last edited:
