My explorer has been running a little rough, particularly at idle. When I take off from a rough idle, it'll run rough until I hit 25-30mph. I ran by O'Reilly's hoping to pick up a pack of spark plugs and be done with it, ended up leaving with a new MAF sensor. It ran better for about 10 miles (I'm a delivery driver, so I did a lot of stop and go immediately), before it ran even worse than it did before, but at least my CEL finally came on. Took it back to O'Reilly's and they read a MAF sensor code and a catalytic system code (didn't ask for the codes, and now realize that was a mistake). So today I took it to a muffler shop to have the catalytic system diagnosed. They looked at it for 10 minutes and told me they didn't think it was the converter. They said it seemed more like the EGR valve or solenoid, or the IAC. He scanned the codes again and got multiple "running lean" codes (0171, 0174, etc). The guy said I didn't have a vacuum leak, so I think I can rule that out. Unfortunately, the truck idled fine the whole time so he didn't feel comfortable giving me a definitive answer. He told to to leave the EGR valve hose unplugged for a few days and see if anything changes. Anyone have any experience with anything like this? I'm thinking about running a bottle of fuel cleaner through it or taking off the IAC and/or EGR and cleaning them myself. Any advice would be appreciated! Thanks guys.

 

Welcome to the forum!

What model year is your Explorer and which engine does it have?

-Rod

 

Thanks! It's a 98 xlt with a 5.0

 

If there definitely are no vacuum leaks, the Differential Pressure Feedback EGR (DPFE) sensor is a logical item to consider. I suspect that's what they were referring to by as the EGR solenoid. The DPFE is sometimes referred to as the EGR Position Sensor. It was a popular part to fail on that vintage of Explorer (as well as several other Ford models of that era).

-Rod

 

Notice the very first word in shorod's last reply. I would trust but verify. Look for a sneak path around the MAF and don't overlook the evap system. Fuel pressure may be low as well. Also, an exhaust leak in the vicinity of the O2 sensors can cause problems, but, of all places, the exhaust shop should have caught that.

 

Okay, so I cleaned out the EGR valve and it seemed functional. Also cleaned out the IAC, throttle body, and throttle body intake elbow and replaced the EGR valve positioning sensor, as well as the spark plugs and spark plug wires (needed to be done anyway). The truck seems to be running a little stronger, but I'm still having the same problems.

 

You have lean codes for both cylinder banks, so checking things that would impact both banks should be the focus. I'm confused though by everything you've replaced, as it seems if they were all installed properly it would cover the likely issues.

Are you positive you have the vacuum hoses correct on the DPFE sensor? They are two different sizes, but not so different as to prevent someone from getting them reversed.

-Rod