ok 2000 ford explorer sport- received in january and the check engine light came on. took it to shop they told me i needed 2 replace o2 sensors and egr valve and clear somethin 2 do with MAF. so i had them do all that and changed the coil pack and spark plugs and spark plug wires. as of rite now i idle @ 500-700 rpms and when i get 2 a red light i have 2 press the gas and the brake or it sputters and stutters and dies. it will also die if i dont watch the idle and keep it above 500 as im going down the road. i get about 10 miles to the gallon rite now. im going to get the codes and will post with more info within the next 2-3 days.
ok so the codes are PO 401, PO 171, PO 402, and misfires 301 thru 306… any reason y i would have misfires on all of those and like i said i recently replaced the egr valve… any help would be sincerely appreciated
P0401 Exhaust Gas Recirculation Flow Insufficient Detected
P0171 System too Lean (Bank 1)
P0402 Exhaust Gas Recirculation Flow Excessive Detected
p0401 - Causes
A code P0401 most likely means one or more of the following has happened:
* The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced * There is a blockage in the EGR (tube), most likely carbon buildup * The EGR valve is faulty * The EGR valve may not be opening due to a lack of vaccuum
In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit.
* Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open * Clean out the EGR valve and/or tubing to remove deposits * Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model) * Replace the DPFE sensor (with a good quality / OEM one) * Replace the EGR valve
p0402 - Causes
A code P0402 most likely means one or more of the following has happened:
* The DPFE (differential pressure) sensor is faulty and needs to be replaced * There is a blockage in the EGR (most likely carbon buildup) * The EGR valve is faulty * The EGR valve may not be opening due to a lack of vaccuum
With a P0402, it is common for people to replace the EGR valve, only to have the problem return. The most likely solution is to replace the DPFE sensor.
* Check the voltage at the DPFE sensor both at idle and when the EGR is open * Replace the DPFE sensor
p0171 - Causes
A code P0171 may mean that one or more of the following has happened:
* The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry. * There could be a vacuum leak downstream of the MAF sensor.
Possible solutions include:
* In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling * Inspect all vacuum and PCV hoses, replace if necessary * Check for a dirty fuel filter and proper fuel pressure
hope this helps
better than nothing! … thank you and if anyone else has any input feel free to reply!
ok and i need to know which book has tha scematics (sp?) for my vaccuum hoses and where i can find the DPFE sensor, egr valve, and MAF. ive also tried finding it online but 2 no avail… thank you!
Ignoring the codes and considering the symptoms I would also suspect the idle air control system.
Maybe the IAC valve and throttle body just need cleaning.