I was driving my 1999 Camry V6 up a hill yesterday and it started stuttering. It hasn’t been accelerating well lately either. I put in some STP fuel injector cleaner and that hasn’t helped - may have even made matters worse. It’s been 2,800 miles since my last oil change. Any suggestions?
Change the fuel filter…If no improvement, how long since the spark plugs and wires have been changed?
Since you mention an oil change - which is clearly not relevant - I’ll assume that you figure oil changes make up the total of car maintenance.
So…what Caddyman said except I’m not even going to ask the question. You should change your plugs & wires (if applicable) and filters. Then see where things stand.
If changing the fuel filter doesn’t work, your fuel pump could be on the way out. I believe the pressure can easily be tested.
However, as others have said, make sure you catch up on all other maintenance first if needed.
Do you have a check-engine light on at any time?
Thanks a lot for the help. I think I changed the spark plugs a year and a half ago. Which wires should I be looking into? Any idea on what I should be spending for a fuel filter and where I should go to buy it?
Fuel filters are terribly cheap, though often difficult to replace.
The wire reference is to the spark plug wires. I don’t know the ignition system on this engine though. It might be coil on plug (COP) in which case it only sort of has wires - the wires are the ignition coils. If it has a typical distributor then the wires should be replace if they are old, and perhaps the distributor cap as well.
In any case, your symptoms can be caused by several different kinds of things. Poor ignition, poor fuel supply, or clogged exhaust.
Since it happens going up hill and on accelerating, that usually means low fuel pressure, and that means filter or pump. If a fuel pressure test is normal, then it could still be the filter, which is both expensive to buy and expensive to replace on this car.
However, it could also be due to a MAF sensor or even an O2 sensor, both of which should throw a code. Even if the check engine light is not on, you should get someone to plug in a code reader to see if there is a pending code. Midas and AutoZone will usually do that for free, unless you are in California.
I heard you mention that when it happens upon accelerating, it usually means low pressure. So could the MAF sensor also cause low fuel pressure? I’m confused because I cleaned the MAF sensor and it got a bit better. Im actually convinced the fuel pump is causing low fuel pressure. Sorry I know this is old, but does anyone know?
I just found out my cousin didnt change the oil in my car for almost 5 years 
She did however keep adding it when it was low 
What is the deal with all these old threads rising from the grave ?