Thread: '98 SE hesitating terribly when cold. Need help!

I have a problem with my '98 Sentra SE. While it's cold and while it's warming up it hesitates terribly in any gear in lower RPM. Sometimes when I let out on the clutch I have to floor it to even get it to barely move and for the life of me I can't figure out why. The issue seems to go away when the engine is fully warmed up but even then it comes back every once in a while.

I have changed out the spark plugs, spark plug wires, the cap, the rotor, the fuel filter, the gas cap, and the vapor canister control valve. I changed the last two because the car had a CEL for a small EVAP leak for a while, but it hasn't come back so far since I replaced them. I also had a CEL for the knock sensor but that hasn't come back either (I figured it was on because of the other code). All of this replaced and it still does it.

Some areas of concern on the car for me are that when filling it up at the gas pump I can't use full pressure or it kicks off. That is still the case even after changing out the vent valve. Before replacing it there was a slight fuel odor underneath the car near all of the EVAP stuff but when I was under there looking around I saw nothing leaking.

The car starts great, idles great, and pulls pretty well when the issue isn't going on. Compression is 170+ in each cylinder on a cold motor so I don't think the engine is dying.

Any ideas?

I would say the Idle Air Control Valve is not working, but that wouldn't answer the fuel tank question. Also, I don't know how the '98 emissions differ from the older models.

With a IACV doesn't the idle tend to bounce around when it's going bad? This thing idles perfectly cold and warm.

I'm guessing the fuel smell deals with the EVAP leak CEL I had. I'm going to crawl underneath it and see if that smell is gone the next time I drive it.

Bad o2 sensor?

bad maf, had the exact same issue you are describing

I'm assuming no CEL to confirm that issue TheSam? Any suggestions on how to go about testing that? I'd need some way to test voltage correct?

Mine does the same until warmed. I know why mine does it though. I removed the coolant lines from the throttle body, and AAC. I also installed Thermoblok spacers, so it takes longer for the manifold to warm.

Check the timing

i would get someone with a scanner to check the live data but im thinking its ur 02 sensor.

x2^

Just make sure everything is nice and tight with the plugs... check the rotor and make sure it's not bent and just check the timing and distro bolts.