Possible FPO = Ford Parts Online
I had a P171 and it was the MAF. BTW - Ford Parts Online's MAF (at least for an 98 2.0L) is remanufactured. It is a genuine Ford part, the rep said they don't make new ones anymore. You'll also get charged a $70 "core charge" till you ship back the old one.
Sometimes you can not clean a MAF. Try disconnecting it seeing if you get your power back. If so, it is the MAF.
