engine knock when I accellerate

[Ronald]

I have a 91 Explorer XLT w/a V6 and only 84k miles.
The problem is this, when I'm accellerating at least (45 mph)it sounds like a knock/rattle is coming from the engine compartment.
It kinda reminds me of what a waterpump would sound like in its early stages of going out.
It goes away when I'm traveling on flat portion of the road or going down hill but as soon as I put on the gas Knock Knock . I dont think its the lifters cause it doesn't knock at an idle. Can anyone help?

Also I get a vibration when I reach 50-65 mph how do I fix this. And lastly, I go through a qt of oil exactly at 3000 miles. I know it leaks out of the valves but how can I fix this. I'm not a mechanic by any means so be clear with your suggestions.Thanks! I'll be looking forward to hearing from anyone!!

Chef

 

[CAC91]

All you need to do to solve the pinging problem is use a higher octane gas. I live at a pretty high altitude (5800ft), but my 91 would ping on 85 octane when the weather got hot. So to fix your problem either burn better gas or don't "get on the gas" too hard accelerating.

 

[SteveVB]

You may want to check your intake manifold for oil at the rear and pull the plugs look for deposits. May need a new intake gasket, or you may get by with retorquing the lower intake bolts. Do a search of this site for intake manifold see what comes up.
The oil from the intake or if you have valve probs could cause the "ping"

 

[2001ExpSport]

Have a tech look at your rig. Your engine is designed to run on 89 octane. Sounds like detonation and can be solved by adjusting the ignition timing.

 

[CAC91]

Adjusting the timing if it is not off will only mask the problem. You'll also lose performance and possibly mileage. Trust me...

 

[TPLYNCH]

Welcome to the site Ronald. I'm sure you'll find answers to your questions here! Has your Mass Airflow Sensor ever been cleaned/changed. I'd start by cleaning that. Is a very common cause of knocking/pinging. Check enging pinging link on the following site for info on how to clean. Dead Link Removed

You will also find lots of other great info there for more common Explorer problems.

 

[Ronald]

Originally posted by TPLYNCH
Welcome to the site Ronald. I'm sure you'll find answers to your questions here! Has your Mass Airflow Sensor ever been cleaned/changed. I'd start by cleaning that. Is a very common cause of knocking/pinging. Check enging pinging link on the following site for info on how to clean. Dead Link Removed

You will also find lots of other great info there for more common Explorer problems.

Thanks for the info. I'm going to check into this this weekend. One last question. As far as the knock goes, is it usually when the engine is warm (in my case 15 miles down the road) when the knock can occure or doesn't it matter?

Thanks again, Ron

 

[TPLYNCH]

I believe it generally happens when warm... has to do with the computer running the engine to different specs (fuel/air mix, etc.) after the engine is warmed up.

 

[PhxExplorer]

In regards to your oil loss, what type of oil filter are you using? The reason I ask is because I was losing oil at about the same rate you are so I posted the problem here. It turns out that the Fram oil filter I was using has a weak drainback valve causing it to throw oil, (I'm not sure this is the correct technical term but it's close). I installed a Mobil 1 filter and changed oil brands from Quaker State 4x4 synthetic to Castrol semi-synthetic and haven't leaked any more oil since and that was about 6000 miles ago. So if your using a Fram filter change it and I bet it will help out your oil consumption problem. Good luck and hope this helps!!!

 

[Dre]

You've come to the right place! Here we go:
Point one: As far as knocking goes, I took my previous Explorer to the dealer and all I got was a sugestion to use higher octane gas. Now on my present one all I use is mid-grade which falls around 91 octane.
Point two: All Explorers are kind of prone to the vibration problem. Installing a steering stabilizer might be an answer here.
Point three: Quart of oil every three thousand? Mine does the same thing. When the light says I'm low on oil I know it's time for an oil change. Keep checking though since that might be a problem later. I have had this problem for the past 50K miles.

All the best with your rig!

Later,