Advice Needed

[Harry P33]

Sorry for raising what must be the same questions, but doing a search results in 1000+ hits and I never find exactly what I’m looking for.

I just inherited my wife's '94 XLT. Here's what I have: Stock with 120,000 miles, original A4LD maintained per OEM, 3.73 limited slip rear, crappy aftermarket exhaust with undersized pipe that makes a pissing sound when throttled hard. Also, a noise has developed under the hood that sounds like a rattle when heavy torque is applied… hitting the gas on the highway or running up hills… never at idle. Otherwise, this truck runs really well.

What can be causing the noise? It almost sounds like a leak from the exhaust manifold, but I can’t find one while idling. Could there be too much backpressure when hitting the accelerator, causing a leak? Or is it the dreaded engine rattle I have heard about?

The tranny is due for a fluid/filter change. I have always replaced them per Ford service schedule, but now that it’s getting older, should I leave that POS tranny alone, or change the fluid/filter as suggested?

I want a new exhaust, louder than stock, but not too loud. What do you recommend?

I will probably change out intake after exhaust, again, please offer suggestions.

Thanks in advance, great board!
Harry

 

[Crankcase]

Lifter knock or engine ping. The lifter knock is caused by internal parts knocking, whereas the ping is caused by carbon buildup in the engine. There are tons of threads on those two subjects...

 

[Bashman]

For exhaust, most people here stick to Magnaflow, Gibson or Flowmaster cat-back. The pipe should be either 2.25" or 2.5". Don't bother replacing the stock catalytic converter since they are already free flowing.
For the engine noise, I would disconnect the battery (min 5mins), remove the mass air sensor and spray an electronic cleaner that doesn't leave a residue on the the little filaments. Re-install, reconnect the battery, ltru nengine on and let idle for 5 minutes then go for a little drive and see if it still makes the noise.
Like Crankcase said, there's tons of threads on ping and lifter knock.

 

[TPLYNCH]

Rattle/pinging when engine is exerting itself is a dirty Mass Air Sensor and/or carbon buildup. Cleaning the MAS is easy. So is doing a carbon flush.

http://www.explorerforum.com/forums/showthread.php?threadid=49295

http://www.explorerforum.com/forums/showthread.php?threadid=76553&highlight=carbon

If the fluid has been changed regularly and no tranny problems, keep changing it per the schedule. DO NOT switch from regular to a synthetic fluid however at this stage in its life.

 

[Harry P33]

Thanks all... I appreciate the input.