My 1999(reasonably well maintained)Ford Windstar with 130,000 miles and 3.8L V-6 idles very roughly, lunges and stalls on occasion if in drive and stoppped. Slipping it into neutral and a slight rev and it recovers somewhat. I’ve replaced plugs, air and fuel filters, idle air control, EGR valve, throttle position sensor and cleaned throttle body. A parts store readout mentioned only the EGR code. Any thoughts? I’d like to avoid a dealership visit.
How about providing the actual code number. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code (like P0123) not just their translation into English and post it back here.
How does it run at highway speeds? Any misfire? Any minor performance interruptions?
Pcv valve clean?
You’ve already mentioned most of the usual culprits, except the fuel pump, regulator and injectors.
I had a the check engine light come on on my 2000 Windstar with the same engine. The readout was a lean-burn condition. I had to replace the intake manifold gasket.
Autozone checked the codes: PO171 and PO174, identified as mass air flow sensor and O2 sensor. Van runs fine at speed on city and highway. What are the chances of this fixing it, if installed? Also, I hear that replacing the O2 sensor is difficult and may damage the exhaust system. Thanks for the replys.
Triedag nailed it. After 3 days with the local mechanic and no diagnosis or charges for his effort, a master mechanic friend in my home town found that the intake manifold (which has 3 levels) required replacement of the gaskets on the upper two. It was running lean based on this leakage and now it idles fine and the check engine light is off for the first time in years. Hallelujah!
Glad you got it fixed. Did the master mechanic say anything about troubleshooting the problem with a vacuum gauge? I hope he did. If the leak was between chambers, the vacuum gauge test might not be definitive; but, now, we’ll never know.