Postby smj999smj » Mon Jul 13, 2015 1:29 pm
Both are possible. One common problem I used to see is that the vacuum hose to the fuel pressure regulator would split at the end and fall off of the nipple on the regulator. This causes the fuel pressure to run at maximum pump pressure to the injectors. The regulator is at the back of the engine, close to the firewall. Reach behind and make sure the hose is intact. A fuel pressure leakdown test would be needed to test for a fuel injector leaking down. You may also want to check the O2 sensor if it has a lot of mileage on it, or even replace it.