i have a1997 Nissan altima 140k miles with manual transmission. i have a fuel problem that i can’t seem to solve. evey 1-2 days and only intermittently and unpredictably my car starts to idle up and down and ocassionally if i dont give it enough gas they car may stall but the stalls only happen when i am not pressing th accelator, meaning only at resting idle. since i am fanatic on washing my engine, i initially though that spark plugs were dirty or not working, i changed the spark plugs thr ditributor cap and the wires but the symptom continues. then i check the resitance of all the four fuel injectors and all of them read at around 12.8 ohms. i have also treated the fuel system twice with injector cleaner, the kind that you find at a gas station but still the problem persist. any ideas. your help will br greatly appreciated.
if it is not too much trouble i have another smaller questions. if the car sits overnight or for a couple days, the shift is really easy but as the car warms up the shifting becomes harder. could the transmission fluid need to drained and replaced?
The IAC valve controls the engine idle speed whenever the accelerator is released.
The shifting problem might be caused by a clutch master cylinder being effected by heat. When this happens, the bore in the master cylinder expands to where the cup seals no longer seal. So when you step on the clutch pedal, there’s not enough hydraulic pressure to release clutch. So it’s like trying to shift gears without stepping on the clutch pedal.
It could very well be what tester describes but that vintage altima had a common problem with a leak in the air intake gasket.
Mine did and it would hunt for idle as well. Under the right conditions with the AC running, it would get close to stalling.
Run the car, take a can of starter fluid and carefully spritz some where the air intake and engine meets, right along the gasket. Not too much but just a little. See if the idle changes when you do that.
If it does, you can get a bit of Indian head gasket sealant, put a bit on a small brush and brush it onto the suspected area where you spritzed and it made a difference. Rev the car a bit as you brush it on - that will suck the sealant in and may very well seal the leak.
Alternatively, you could take the air intake off and replace its gasket but that’s a major pain on an Altima. Its hardware are very hard to get to. (ask me how I know that…)