Hello. I own a 2002 Maxima with 102,000 miles. For a while, the car has been making a rattling noise while I am driving and pressing on the gas pedal. The noise occurs frequently whether starting from stopped position or accelerating while driving. The engine has checked out fine and a suggestion was made that I use’better’ gas. I filled up at Chevron with '89, which is the grade I have always used but at discount gas stations. The noise however continues. Is anyone familiar with this problem or can offer a guess at what may be causing the rattling, clicking, tinny noise? Thanks!
The noise might be pinging or pre-ignition. This is when the fuel/air mixture ignites at the wrong time.
One thing that can cause this is using cheap gas. Cheap gas doesn’t have the detergent levels that can prevent carbon deposits from forming on the intake valves and the piston tops.
When carbon forms on the piston tops, it raises the compression of the engine. When carbon forms on the intake valves, it can absorb some the fuel that’s supposed to go into the cylinder causing a lean condition. So you have an engine with high compression without the right octane gas to prevent the pinging.
To see if this is cause, the next time you fill the tank, put a high octane gas in the tank. Such as 92 octane. If the pinging goes away, then the compression of the engine has been raised from carbon deposits on the piston tops. Because your vehicle doesn’t require high octane gas.
This doesn’t mean you have use high octane gas from now on to prevent the pinging. Instead, stay away from the discount gas stations and keep filling the tank with Chevron gas.
Chevron gas is a Top Tier gasoline. Which means it contains a higher detergent content than the discount gas. This prevents carbon build-up, and when used over time can actually remove carbon deposits.
Tester. Thank you so much for the suggestion and taking the time to educate me on how my vehicle uses the gas I put into it. The link you provided is very helpful.
Is it for sure the engine? It could be a loose exhaust heat shield.