Car stumbles while cold during acceleration

[dysfunction8]

I'm new to the board and am looking for some advice. I own a '99 Sentra and for the 2 time ever am having problems with it. After the car has been sitting overnight or for any extended period of time (4+ hours) the car stumbles during acceleration. Once it warms up, the problem seems to disappear, except for once in a while during driving it might fall on its nose for a second, then it's fine. It's not throwing a check engine light, and ive done a basic ignition tune up and replaced the fuel pump. Replacing anything else is going to start getting expensive and I'm quickly running out of cheap ideas. Anything will help. Thanks.

[nametakennow]

How's your water temp gauge reading?

Sounds like a bad thermostat to me.

Welcome to NICO!

[dysfunction8]

Temp gauge reads within its normal range. I had someone tell me to check the TPS and CPS as well.....I'll see what autozone can tell me

[nametakennow]

Both are possible but less likely since it's cold-only.

It can be hard to tell if the thermostat is accurate because the gauge only shows a very vague range, but I figured if it was reading screwy it'd be a tell-tale sign.

Anyway, get the TPS and CPS checked, but if those are fine then go ahead and replace the coolant temp sensor.

[dysfunction8]

Well, apparently autozone cant test either of those (or so the angry old man tells me anyways), and the coolant temp sensor is a cheap so I'll give it a try in a day or two. I'll let you know.

[denver_gxe]

my car did that at the beginnign when the MAF was on its way out. but it only stumbled when cold. when it was warmed up it was fine.

[denver_gxe]

if you have a dvom i can get you the specs for the maf, along with specs for the other sensors

[dysfunction8]

I have a multimeter, does that count? It measures voltage and resistance.

[nametakennow]

Yeah, you could use that to check the sensors. Look up the specs in the FSM (link in my sig) and compare your readings.

[denver_gxe]

i will post specs in the morning.

[dysfunction8]

I tested the MAF 1.17 at idle when warm, and I dont have a tach, so i cant really test it at 2500 RPMs. Now, something i forgot to point out is that the car doesn't stumble when idling or when its out of gear and i rev it...It only does it when there's a load put on it.

[dysfunction8]

Also, the TPS checked out fine. but I'm not sure how much good checking these things are if the motor isnt fumbling and stumbling while im checking them

[dysfunction8]

Well, I used the Self Diagnosis Program on the ECM, and it gave me a code 0505. So, I think I'm going rack it up to an act of god and wait til something actually breaks on the car so I know what to fix (Since my car says nothing is wrong at all) Maybe I just had some bad gas or something. Thanks for your help guys.