Thought I would try the vast knowledge here. I posted it in a different section but I think you guys might know better here. I know it isn't ford related but I have found good answers for my Expedition so I thought what the hay. Below is the post:

Recently, I have experienced a similar noise on two separate cars that I have driven. One is mine and the other is a relatives. Both are not normal and would like to save some money by fixing it myself if possible. One is a 93 subaru impreza and the other is a 00 Linclon LS V-6. The noise occurs after the car is warm and it is under acceleration. It is a rattle type noise coming from the engine compartment. It only occurs when the car is in drive and does not occur while reving in neutral and is more prevalent when the car is warm. Both cars are in need of a tuneup and was told by a mechanic that it might be fuel related. I know for a fact that both need new fuel filters, could this noise be related to that somehow? Any suggestions would be very much appreciated. Thanks in advance.

Brian

 

Are we talking about a ping here. Sound like someone dropped a bunch of marbles in the motor? Sounds more like an EGR problem.

 

Sounds like fuel filters and tune ups are in order. You have detonation (pinging). This is when hot spots in the combustion chamber fire the fuel mixture before the spark plug, thenwhen the plug fires, the two flame fronts crash together which gives you the pinging/rattling noise. It will ruin an engine if not addressed soon. It can be caused by cheap gas, carbon build-up, a lean fuel mixture, or too much advance in timing. ( Timing is not ajustable on these cars so not an issue here). You may want to try a upper engine cleaner treatment to reduce carbon build-up. I have read here that a lot of people here like a product called Sea-Foam. I have never seen it so I have no input there.

 

On the Lincoln, the dealer recently replaced the MAF sensor because they said it was bad and was causing the emission light to go on and they also cleaned the injectors. After that, the rattle seemed to get worse. They still recommended a new fuel filter which has not been done yet. Could a clogged fuel filter be causing the car to run lean and thus causing the ping? Thanks in advance.

 

It's possible but I would think that you would get drivability issues as well. It is happening when it is warmed up, under a load, which tells me that your combustion temp's are too high (this is what the EGR is for). I suspect that you either have carbon built up on your pistons, in your EGR passages or an EGR vale that doesn't work. What kind of milage are we talking about? I don't like to tell people to do what I do but, to clean off the pistons, I'll run on the freeway, leaving it in second gear @ about 50mph. Yes, it will scream( that's why I don't like to tell people that) after about a half mile it usually lets out a big cloud out the back. They make some pretty good cleaners for that also but they usually take out your oxygen sensor.

Anyway...change your fuel filter and then check your EGR to make sure it works right. Check to make sure it has vacuum at 15-1800rpm's, thenmake it open at idle and it should kill your motor. Also check your owners manual to make sure you are running a high enough octane fuel.

One more thing would be a bad knock sensor. (that usually sets a code though) To check that you could use a timing light a lightly "tap" the engine with a hammer. You should see a change in timing. The computer should retard it when it senses a "knock".

 

I would look it the EGR valve. Subaru had a problem (recall) like that some years ago and it sounded like a rattle.