My '98 (68k miles)Duratec has been making a whooshing sound from under the hood during hard acceleration. I began to notice it when the outside temperature started to dip below about 15F. It seems to coincide with the activation of the IMRC above about 3000 RPM but only when the engine is under heavy load. It does not happen when the engine is gunned while in neutral. Fuel economy has dropped a bit but this might have more to do with the average temperature being about 10F over the last week or so.
I have looked for loose hoses all over the engine compartment and have found nothing.
I have read a bit about the DPFE in this forum, but several things are not clear to me.
1) Where is the DPFE (if so equipped)located on a '98?
2) Will a DPFE problem generate a CEL?
3) Does the outside temperature really have anything to do with it, or is it my imagination?
4) If the worst has happened and my precats have failed, what do I tell my LM service manager to persuade him to investigate the precats in the absence of a CEL? I assume that I have a little time to get these replaced before the 7/70 limit.
Any help would be greatly appreciated. Thanks.
