rough idle

i have had this 01 explorer for about a month and it idles rough. also trys to stall when shifting from reverse to park or drive. no check engine lights are on. in my old explorer(it was a 99) it had a rough idle. now i have just changed out egr valve, egr dpfe sensor and egr vaccuum regulator. they where changed out because of a po401 code. it kinda felt like it was missfiring at 40 mph and it had a rough idle . but when i changed out all the parts, it fixed that problem, except for the rough idle. can someone help me

I would try checking your spark plugs sometimes and very rarely something or your piston will hit the spark plug and close the gap, try looking at those if not change them out along with your spark plug wires. and if its not that you could try your ignition coils. but first I would check those spark plugs

Which engine does you Explorer have?

You may want to check the PCV valve and associated plumbing. Also, pull the air intake hose and inspect the throttle plate in the throttle body. It may be carboned up. Be sure to open the throttle and check the back side as well. If there is quite a bit of carbon there, then pull the Idle Air Control (IAC) servo as well and clean it with throttle body cleaner that is safe for coated throttle bodies. I've been very pleased with how well the STP throttle body cleaner works.

Another item to check would be the Mass Air Flow (MAF) sensor. You'll need a set of security Torx bits to remove the sensor from the mount in the air intake hose, as well as some CRC MAF sensor cleaner (available at Advance Auto Parts). Clean the MAF, let it air dry, and re-install.

-Rod

its a 4.0 sohc

Alright, I don't believe your 4.0L SOHC has a serviceable PCV valve, so scratch that. The other items still apply though.

-Rod

well i tried cleaning the IAC and the MAF. the IAC was really dirty. it really helped. it seems to idle higher and doesn't idle rough. i took it around the block. it drove great. but when i floored it, it wanted to go but was hesitating. it seems when i give it gas it is holding back or going and then hesitating, going and hesitating.

If the throttle body was very dirty, you may have quite a bit of carbon built up on the valves. It may take a few trips to get the carbon burned off. I don't really think this will be your case though.

Does the engine seem rough when hesitates, or is it smooth, just doggy?

-Rod

smooth

after a week of driving it, still idles rough. but not as bad as it did before. i am running out of ideas

Fuel Filter


Dr98

yeah, iam going to change the spark plugs again and will try the fuel filter also. thanks

well sorry i haven't replied with the results from all the suggestions everyone has helped me with. i have been busy with school and work. but today i finally change the plug wires and it has helped. whoever did them the last time did not change the hard to reach ones. i am still going to change the fuel filter when i get some cash.