A few weeks ago my truck (98 4.6) started pinging when you suddenly gave it half to full throttle. I cleaned the MAF and dumped in some injector cleaner and the next day it stopped. (This may just have been a coincidence) There was no change to gas when it stopped pinging, still regular. I have also since changed the fuel filter.

Then two days ago it starts pinging again under sudden medium to full throttle. I again clean MAF and use injector cleaner but this yields no results. I switch from regular to super and this makes a little difference but it still pings.

Can someone give me any ideas on what to try next?

Motor has 57,000 miles and I am thinking to get plugs changed soon but who knows if that will help.


Thanks!

 

Sounds like EGR issues.

 

How do I check the EGR system? Is it tough to get to the valve?

Sorry but I am used to non computer engines where an egr valve is like $3 and five seconds to replace.


Aha! Found this..

http://www.calink.us/f150-egr/f150-egr-page.htm

 

same problem with my 97 4.6 started pinging around 60,000 mi. tried many fixes posted here but nothing helped. At 105,000 mi. I had the intake manifold off for a repair and decided to replace the knock sensor-no more pinging not even at wot with reg gas never had check engine light. upon inspecting the old k.s. it was full of rust. As far fuel injectors being dirty I have never put anything in the tank other than gas and the injectors looked like new no deposits whatsoever. I'm now at 114,000 and still running great

 

Also, try cleaning your MAF.

You might want to get a Haynes or Chilton's manual. While folks may disagree on which is better/worse, a decent service manual can really help out. Many issues are minor and easily fixable with just a li' bit of direction.

 

Ok, two questions for the guys who have posted on here. One, what is the MAF? And second, how expensive is a new knock sensor and how hard is it to change? Because I have this same ping problem. Thanks.

 

MAF is mass airflow sensor measures how much air is entering your engine
knock sensor $70 must remove intake manifold it is located top center of block
sensor easy to change once you get to it. I recommend a ford truck service cd got mine off ebay very detailed info

 

OK I checked my EGR by sucking on a hose to create vacuum and could hear it close. Then I started the truck and did the same thing and the idle dropped. So the EGR valve appeared to be working.

Next I removed the EGR vacuum solenoid. I nearly destroyed the cap getting it to come off. (cheap design garbage). The air filter in the solenoid did have some dust in it so I washed the filter out with some water and put the cap back on and put it back on the truck. If not for the cap issue could have just done it while it was mounted. But only one nut to remove it so no biggy.

Went for a test drive and no pinging so I am hopeful that was the issue.

Thanks to ProjectSHO89 and ccculbreath for advice on troubleshooting the EGR system! And Mike not Jordan for the initial EGR call!


Flow-Master
Assumimg your truck is like my '98, the MAF is located in the air filter hose on the engine side. If you undo your air filter clamp and look down the tube you will see it is the little device with two small wires running across it.

To clean it you can get some CRC electrical parts cleaner (about $5) they also now make a cleaner just for MAF. I used the regular stuff. So you just spray the cleaner at the MAF real good and that's it. You do not want to ever touch the wires with anythng other than the cleaner.