Edmunds Answers

Voted Best Answer

  • avatar actualsize 04/20/08 11:26 pm PST

    Maladjusted valves and engine ping are two different things.

    If your valves are out of adjustment, fuel octance won't make any difference. The valves are not easily adjusted, because I'm pretty sure they are the shim and bucket type. Unless you have the experience, tools and an assortment of shims, I'd pay to have someone else adjust this type of valves--if indeed that is the problem. And 10 years away from underhood work tells me that maybe this isn't a DIY job.

    You can try premium fuel for a couple of tanks; if the symptoms disappear, you've got something other than valve noise going on. What higher-octance gas improves is engine knock (aka ping). It is pre-ignition of the fuel, something that happens if you use fuel with too little octane. And this will be most noticeable going up hills or pulling a load.

    Something to note: In the search for cheaper fuel, some are venturing to off-brand gas stations, where regular can be 86 instead of 87. Make sure this isn't your problem. In my area, there is one major fuel retailer that is known for low prices that sells sub-standard 86 octane as regular. I never, ever go there.

    I'm sure it could stand new plugs and a new air filter, but at the end of a day, a 145k mile engine might be due for a check-up at a mechanic.

Answers

  • actualsize 04/20/08 11:26 pm PST

    Maladjusted valves and engine ping are two different things.

    If your valves are out of adjustment, fuel octance won't make any difference. The valves are not easily adjusted, because I'm pretty sure they are the shim and bucket type. Unless you have the experience, tools and an assortment of shims, I'd pay to have someone else adjust this type of valves--if indeed that is the problem. And 10 years away from underhood work tells me that maybe this isn't a DIY job.

    You can try premium fuel for a couple of tanks; if the symptoms disappear, you've got something other than valve noise going on. What higher-octance gas improves is engine knock (aka ping). It is pre-ignition of the fuel, something that happens if you use fuel with too little octane. And this will be most noticeable going up hills or pulling a load.

    Something to note: In the search for cheaper fuel, some are venturing to off-brand gas stations, where regular can be 86 instead of 87. Make sure this isn't your problem. In my area, there is one major fuel retailer that is known for low prices that sells sub-standard 86 octane as regular. I never, ever go there.

    I'm sure it could stand new plugs and a new air filter, but at the end of a day, a 145k mile engine might be due for a check-up at a mechanic.

ADVERTISEMENT

Top Toyota Sequoia Experts View More

Rank Leader Points
1. MrShift@Edmunds 155
2. WyoTex 50
3. Stever@Edmunds 45
4. boomchek 35
5. texases 35
6. morin2 30
7. 0patience 25
ADVERTISEMENT