My 97 F150 4.6 detonates on regular gas. At the price of gas, it is getting annoying filling this think with mid grade or premium! But I know the timing is computer controled so do I have a choice or am I stuck paying for expensive gas the rest of this trucks life?

 

Have you changed the plugs recently? Sometimes detonation can occur from carbon build up. Or some sort of metal build up in the gap which can short the plug.

As far as gas prices...only looking to get worse... over the long run, you may get savings from a tune up if haven't looked into it in 50k miles.

The only thing I can think of as far as engine tuning and computer programming would be to get a PCM flashing type of programmer. All of the chips that are performance style usually force you to run on 91 octane or up. There are chips that allow changing shift points and engine timing, but not the type of timing you're talking about (I assume that would be retarding it to fire the spark sooner to prevent preignition), it may cause better performance on the hwy at speed, but in the city it would lag with a power loss and worse gas mileage.

The PCM flash programming tools allow you to change certain aspects of the ignition timing (I think static, but not dynamic... help me out here), and can be pretty expensive- more than a chip. Either might never pay for themselves, and that would put you back at your point now, trying to save money.

-Kerry

 

Just did a tune up last week. The truck developed a miss about 3,000 mi ago and finally was running so badly it wouldn't go over 45mph. So we just changed the plugs and wires, I hadn't even thought about running normal gas again just to see. But my low fuel light came on on my way home tonight so I'll try that tomorrow.

I had thought about getting a chip to enhance performance but I haven't researched enough to see what their fuel needs are. Right now, I've about had it with the truck and am not sure it's worth the $350 month payment plus the money I have to put it in to keep everyting working correctly! If only they were all made like my '86 Mustang GT with 230,000 and still running with pretty much stock everything! If it weren't for that car, I'd probably write off Fords!

Thanks for the info. I'll let you know how the next tank runs.

 

Try cleaning your MAF sensor. A dirty MAF can cause a ping. If you do a search on here you'll find instructions on how to do it.

 

Thanks for the info. The new plugs and wires seemed to do the trick. I put low octane in today and even towed a car and didn't have any detonation. If I have any more problems though, I'll check my MAF. Thanks!