if theres 89k on the clock and your coils are original youre actually wasting money by NOT replacing them asap... but that begs the question: are your coils original and are they under extended warranty? i dunno about an 02v8 extended warranty.. maybe someone that has one can chime in. i think the extended warranties are detailed in tsb's/recalls for the given year, so you can search those. dont expect lincoln/ford to help you, or be truthful with you, or even fix them without a fight even if they are warrantied.
to determine if they are original coils is tough, but generally you can look at the top of the modules. if they are all motorcraft and they are all the same they are probably originals.. but then again theres really no way to know for sure abt the age. the only thing that is for sure, is that youre lucky to get over 60k out of coils. so if those ran for 89k just know that they are past their useful life and are a ticking time bomb. its best to replace them all at once bc one old one could damage any new ones.
i dunno if you have an advance auto close, but i got mine there with a lifetime warranty and took advantage of their coupons. a coupon for buy $50 save $20 or buy $100 save $40 <sometimes save $50 off $100 too> is the best way to go. break up the orders if need be, to use more than one coupon. i dunno the current coupon code, but if you search slickdeals.net for advance auto you will find the coupons i described.
the advance auto coils are by bwd/intermotor <it might be 'bdw', i dont recall>.. but anyways theyre made in usa, have a lifetime warranty, and are like less than half the price of the motorcraft/visteon/oem ones, which are no warranty and chinese... i have the bdw/intermotor ones from advance in my ls, an 05 v6, with zero issues. i wouldnt imagine they are much much diff v8-v6. i would caution against getting any brand other than the bwd/intermotor or the motorcraft/visteon or other brands that come recommended by someone successfully running them here bc you could be throwing money away. personally, i say stay away from motorcraft/visteon/oem bc they are known to fail around 60k, so obviously they are KNOWN to be somewhat subpar and expensive. might as well grab something with a warranty. plus the bwd/intermotors are usa mfr vs motorcraft/visteon/oem being china mfr... thats almost a no brainer to me.
but back to your question, how much does a maf play into 'it'?? who knows... your issue isnt 100% clear. 'fuel smell', 'hard start', and 'lower mpg than expected'... are you sure its an abnormal fuel smell? what exactly do you mean by 'hard start'? obviously it did start, so what is the idle rough or something? 'low mpg' these cars typically get worse mpg than listed on the epa sticker... how many mpg are you generally talking abt?
so youre issues maybe leaning towards normal... no way to know for sure over the internet. my cheap guesses would be clean the MAF, change the fuel filter, and run injector cleaner. if your problems are overstated then the 3 of those should cure it. i think your problems are overstated bc you dont have a code or a significant issue when driving the car such as hesitate/poor shifting/wrench light/other check engine light worthy symptoms. if it were running rich i would imagine you would have a code for that as well.
so yea the others are probably right to say coils.. but there are a few other things you need to do anyways <maf, fuel filter, injector cleaner>, so you might as well do those first before you throw the coils at it...
and fwiw, to the ppl being useless twd the new ppl... this guy has a motor with 89k... no matter the price tag why the fck would you scrap it?? get real. if he had 289k then youre maybe in the ballpark with that comment.... then the ppl who are sayign blah blah def coils go search etc... he doesnt have any other typical failing coil symptoms described... no missing, no hesitating, no wrench light, no check engine light, etc.
he may be a new guy, but his questions are 100% legit. if you dont like it dont read/comment... pretty easy...