Thanks for the info. I will make sure my mechanic will check all these you suggest, The #4 plug seems ok but looks powdery white.I will check and get back on the compression reading on # 4 test.

thanks again

jdc

 

I spoke to my mechanic and find that injector # 4 is functioning well..( darn ).
earlier comments : New plugs,wires,injector flushed,new coilpact,no leak,
presure test good,

desperate
96awdtoronto

 

Vac leak can cause all sorts of problems that you can associate with other things that could be wrong. With any ruff running and poor speed increase check all the vac lines first and dont miss the one thats going to the tranny.

 

IF you suspect a vacuum leak, a simple test can be made with a vacuum gauge. In fact, the gauge can be used to diagnose all sorts of problems, even these newfangled computer controlled engines with EFI. It's cheap too.

 

...EGR ok, all injector's good,check all possible leak...Man ! we are both stressed !!We checked all possible cause including all you guy's input here in this column.So we decided to close it back !! retorque all intake manifold and plenum bolts..and hoping these will fix it !! as well as replacing with new set of NGK spark plgs.
Guess what ? Rough is gone ! Well right now it's unbelievable !! it start right away and no hesitation, It was raining here in Toronto and it took me a while to drive back home,I drove it for more than an hour and boy ! It has been a while I have not seen this van run agreesively strong..but I must admit I'm a little bit "paranoid" driving back..i'm just hoping it will not run rough again.
She never complain on a regular ( 87 octane ) gasoline for over 10 years..well I ocassionally feed her 89 octane when i'm driving long distance, so I was thinking maybe I should switch to higher octane from now.
Well guy's I appreciatte all feedback ! and hopefully my experience will help some one in the near future..and I will let you guy's know how my 96awd will behave going forward I will continue reading and and learning from the PRO.

96awdtoronto

 

Hey, good news for us all. Denso iridium spark plugs are of the correct heat range and they last longer than double platinum plugs. This means we can install plugs and change them less often. So if wee get Motorcraft wires and Denso plugs, we are set. Bad news is Autolite is soon to discontinue our tradition double platinum plugs.

The Denso part# is IT16

 

May be $20 a plug

 

4L Aeros sont couple et les monstres de puissances en chevaux... apprécient