WEll update for today it seems the shocks fixed the clunk....But the check engine light came back on again. They have replace the Mass Air Flow sensor and it still does it? What else would throw a restricted performance light and low fuel pressure in both banks?

 

many things.

my fathers 2000 xj8 had this, hit up the forums and was told to

replace air filter
fuel filter
partload breather hose
clean maf
and spray down the throttle body

this fixed the problem.


run some Shell V-Power fuel system cleaner through your system,


and i was also told to use quality bp or shell gasoline. based on your timelines i assume the gas in there came with the car. ill bet the house on that being 87 octane from 'friendly gas & shop'

 

Yes I agree that they more than likely they put in some crappy gas the way it jerks around when you really give it gas makes me think that it has some bad gas in it. They have changed the air filter, the MAF, cleaned the throttle body as well. I guess now its just a waiting game

 

put fuel treatment in the tank. and top off with BP or Shell 93 octane asap. take it easy on that tank, then do it again and see if it persists.

make sure all the connections are tight and secure, all the intake tubes, oil cap, dipstick. all vacuum sources are secure.

 

My brother borrowed my Bike for a week, so I had his Mercedes 500SL for a few days. I mistakenly filled the tank with 87 octane (from Chevron) and it HATED it! The car bucked and coughed badly. I put octane boost in it till the tank was dry (helped a LOT), then I refilled with 92 octane (cant' find 93 octane here in Placerville ), and all was good again. This was before I bought my XJR, so I've never made the same mistake in my XJR, YET.

 

yes, when i was younger i had a 91 q45. i was oblivious to fuel octane ratings at the time.

my father would always tell me ONLY put 94(was available then), so i always did.
then one day i had an question > why am i putting 94 at $2 a gallon when 87 was $1.40.

so i put $10 87 in, as im driving i was like " why is my car acting funny, why the hell does it not have power and why is it so quiet ?? "

then i figured its from the gas, so i just put it in 1st gear and waisted that gas really fast, then refill with 94 from sunoco and all was well.

in short, my 2008 civic which was designed for 87 octane, drives like **** with 87 octane and i only put 93 from shell in it.