Thread: What is this?

Done that! No improvement. I even tried with another MAF, no change. Did the O2 Sensor test, no change.

Now, I discovered that it has an exhaust leak in two places, at the manifold where the head is, and where the flex pipe connect with the manifold. Can this be the problem?

BTW, the onboard diagnostics on these cars are somewhat useless. My MAF voltage was half of what it should been before i cleaned it and i got no CEL. I didn't get a pending one either.

My knock sensor was bad, i didn't get a CEL for it either. It was only revealed to me with a code scanner, looking for pending codes.

Anyway, exhaust leaks do affect torque, more particularly at low RPMs. You could be on to something. It's worth fixing your leaks anyway.

If a sensor doesn't change how the car runs when you unplug it that means it is bad. This works for the TPS O2 and the MAF, That is according to the FSM.

The leaks after the O2 sensor aren't going to effect how the motor runs. If there are any before it they won't unless they are really big.

Um.. that's over generalizing. OBD2 ecus cause the engine to reduce power, not run at all, or assume certain values, depending on what sensor is not plugged in or is outputting data outside of normal range / behaviors.

On OBD2 cars, the two OBD2 sensors have different purposes, so it depends on which one you're talking about.

Can I get an aftermarket O2 sensor? Nissan ones are expensive.

Yeah Bosch are the same thing, same company and all.

Lol... not exactly, dude. There are hundreds of companies that manufacture oxygen sensors..... some better than others.

I can vouch for Bosch / NTK(Aka NGK) oxygen sensors. They are reasonably priced, have an excellent reputation, and i have not heard of anyone having problems with them, ever.

p.s. what header did you get, mr se-r?

None! I found a OEM flex pipe in good condition. I going to put new gaskets, I want to keep this car stock. I'll probably sell it soon to get something else. Will see.

Ok, I guess I hit the nail on the head. Disconnected the coolant temp sensor, started the car, got the usual, high idle, CEL, fan were running constantly, BUT the hesitation disappeared COMPLETELY. Can this be the problem? Can a coolant temp sensor be bad without the normal symptoms like high idle, CEL, ect?

This one is kind of tricky? Anyone.

Wouldn't hurt. They're decently cheap but a pain in the ass to get to if you're trying not to get too messy. But again, it won't hurt.