Your pinging could mean that you are running lean. As such here are a few things that you can check that are the most common causes on these engines.

Check the PCV valve. It should be clean and rattle when you shake it.

Clean the EGR valve and passages. These trucks are known for carbon blockages here.

Clean the IAC valve. Another common problem that can screw with airflow and cause a lean run. especially if t is intermittent

Check carefully for vac leaks. A vac leak lets unmetered air into the engine and the PCM can have trouble properly compensating.

Test both your air and coolant temp sensors. Inaccurate readings from these can screw up your computers fuel adjustments.
Same for your O2 sensors.

Check the catalytic converter for rattles. If the cat is broken up inside it can restrict exhaust and cause engine pinging. If it gets bad enough a whole host of other problems can pop up.

Let us know how the checks go.

 

hey,thanks for the reply and input. Today i cleaned the engine using the "cocktail" from the forum. Also took apart and cleaned the maf sensor and egr.
Maf was alittle dirty but overall was very clean looking. The egr was black but not blocked and plunger moved very freely. Checked for vac leaks and found none.Pcv valve was clean and rattles.Banged on the cat and no rattles. Didnt have a chance to check the iac,air,coolant and o2 sensors yet. after all was done i still have the pinging on acceleration and is very annoying.No check engine lights though. I did notice after running several errands after the work was completed that the pinging seems to be intermittent.By that i mean it seemed to diminish somewhat on each startup to my next destination.Which now makes me wonder more about the iac (this i know has never been replaced) since you mentioned the intermittent issue along with your reply on the iac check. What do you think! Other than the pinging and poor gas mileage,the trucks starts and idles good and once my speed levels out all is well. Could the knock sensors be an issue,and if so,what is the best way to get to them and replace. From underneath the truck and would i need to remove anything to make access to them much easier.
Hey, one more thing. Attempted to change the fuel filter today as well and could not get the wrenches (16mm & 21mm) on either end of the nuts. And if i did manage to get them on there was no room to even loosen them a 1/4 of an inch. What gives,is there an easier way.
Again,thanks to all who replied with their comments your help has been greatly appreciated. Great forum and kudos to the admins,you do great work.
96 blazer 4dr LT (185,500 miles and counting)

 

Fuel Filter
Not familiar with a 96 fuel filter but if they are anything like 1st gen S10s you should be able to loosen the fittings as they just slide down the line after you get them loose. (I use a 16mm for the fittings & 20mm for the filter). Did you loosen the clamp that holds the filter? You're not going to get it off if you didn't. It sits in there pretty tight when the lines are tightened up. 10 mm wrench and patience is what you need here.

 

I have a 2000 Blazer with 134,000 miles that seems to do the same thing that yours is doing. Mine had made that noise since we have bought it with 57,000 miles. My opinion is to just drive it until it blows up. I have spent I dont know how much money trying to get my blazer to stop making a pinging noise. I have a new fuel pump, fuel filter, cat, new fuel injection spider, new EGR, cleaned MAF, seafoamed the crap outta it,had it put in the diagnostics, premium fuel and all this with no results. I guess it could be the IAC or maybe a knock sensor, but mine is not throwing any codes. I have heard that the noise could be piston slap, valve train ( I recently changed my valve cover gasket and my rockers are non-adjustable, I did not know that, its screw-in roller bearing rockers), sloppy timing chain, and many other things. I have come to the conclusion that my engine just makes noises, it runs strong and gets great gas mileage. I figure if it isn't gonna blow up from whatever that has been causing it to do that for the last 80,000 miles then its not that big of a deal LOL, I just turn the radio up.