Driving the other day to pick up gobble-knows-what when the X started loosing power and shifting very roughly. At red lights (idle) the rpm's would drop to almost nothing, it would sputter and flutter then go back to normal for a few seconds, repeat... It doesn't have enough power to get above 40mph, and has brief periods of shake free operation lasting no more than a few seconds. There is a slight squeaking noise that can be heard coming from the belts or the engine itself... No other strange noises, it just sounds like its choking out. (maybe a wrong fuel/air ratio?)
So far I have: replaced the distributor rotor (no effect), replaced the distributor cap (no effect), put in new distributor lines (no effect, but they look pretty), installed new spark plugs (you guessed it, no effect), tested and cleaned the MAF, it has a clean air filter, snorkel isn't clogged, tested the throttle position sensor, tested the air change temperature sensor, SeaFoam'ed the gas and directly into the vacuum lines (again, no effect), attempted to replace fuel filter (don't think that's the problem), disconnected all of the exhaust O2 sensors and it didn't change a thing...
Some background on my X: it had the timing belt and water pump replaced at somewhere around 110,000 (currently at 160,000). Knock sensor was replaced last year. A few months ago I got a "SERVICE ENGINE SOON" light. It was not blinking so I figured it to be an exhaust insure. Had the codes read and found out one of the exhaust O2 sensors was bad, so I replaced it, and the light went away. But a few days later the light came back on, so I disconnected the battery and the light went away. About a week later it came back in, and was complaining about two of the other O2 sensors, and the one I just put in "O2 SENSOR LOW VOLTAGE". And this past spring my X was subject to an assault from some malicious devil-squirrels who built a nest in the engine bay, ate through the main wire harness, and the engine wire harness, as well as all but two distributor lines, oh, and they did this in one night. Needless to say I had it towed to Nissan where they replaced the engine wire harness and the distributor lines, and since they couldn't get their worthless, good for nothing hands on a new main wire harness, they re-wired the existing harness.
So in short - my engine is dropping rpm's something fierce at idle, and I have no idea why. (it has already been suggested that I check the fuel pressure regulator but to get at it, apparently one must remove the intake manifold... That didn't go over so well last time)
So far I have: replaced the distributor rotor (no effect), replaced the distributor cap (no effect), put in new distributor lines (no effect, but they look pretty), installed new spark plugs (you guessed it, no effect), tested and cleaned the MAF, it has a clean air filter, snorkel isn't clogged, tested the throttle position sensor, tested the air change temperature sensor, SeaFoam'ed the gas and directly into the vacuum lines (again, no effect), attempted to replace fuel filter (don't think that's the problem), disconnected all of the exhaust O2 sensors and it didn't change a thing...
Some background on my X: it had the timing belt and water pump replaced at somewhere around 110,000 (currently at 160,000). Knock sensor was replaced last year. A few months ago I got a "SERVICE ENGINE SOON" light. It was not blinking so I figured it to be an exhaust insure. Had the codes read and found out one of the exhaust O2 sensors was bad, so I replaced it, and the light went away. But a few days later the light came back on, so I disconnected the battery and the light went away. About a week later it came back in, and was complaining about two of the other O2 sensors, and the one I just put in "O2 SENSOR LOW VOLTAGE". And this past spring my X was subject to an assault from some malicious devil-squirrels who built a nest in the engine bay, ate through the main wire harness, and the engine wire harness, as well as all but two distributor lines, oh, and they did this in one night. Needless to say I had it towed to Nissan where they replaced the engine wire harness and the distributor lines, and since they couldn't get their worthless, good for nothing hands on a new main wire harness, they re-wired the existing harness.
So in short - my engine is dropping rpm's something fierce at idle, and I have no idea why. (it has already been suggested that I check the fuel pressure regulator but to get at it, apparently one must remove the intake manifold... That didn't go over so well last time)