# Bad acceleration when hot.



## A_L_E_X1 (Nov 5, 2004)

Hi everyone!

Here's the story (I read similar ones, but couldn't find a solution).

When the car is cold (been outside for a couple of hours, or overnight), it runs OK. I can even press the acceleration pretty hard, it accelerates great. After the engine gets to normal temp (temp gauge in the middle), I can't get off the Stop signs easily.

No difference how much I press the acceleration pedal, it has a very hard time accelerating until it reaches about 20-30KM/H. Also, it kindda makes a small push-pull motion and the RPM gauge jumps from 2 to 2.2 to 2 to 2.2, etc.

Then, when 20-30KM/H are reached, the car makes a small jump forward (as a result of a sudden acceleration, but I keep the same pressure on the accel. pedal) and works fine.

After this point, the more stops I do, the harder it is for it to accelerate.

Here's what was done, but the problem remained: changed transmission fluid and filter, changed fuel filter, cleaned up the distributor (which was quite dirty). Checked the spark-plug wires, the longest one was ~10K and the shortest ~2K, but all of them were continous. Also, I inserted a screwdriver into the spark wire (after disconnecting it from the spark) and put it near (without touching) the engine. I could see sparks (yellow-orange) from all 4 of the cables. This test was done with a cold vehicle.
All the liquid levels and colors were tested and are OK.

Before those changes, the car would simply stall when hot and I had to wait for about 10 minutes to start it again.

The mechanic said that I should change the distributor (which he offered me for ~600$), but that doesn't make sense to me, because if the distributor was bad, the car would've doing that all the time and not just when it's hot.

I checked the ECU (the check engine light was off), gave me a Knock Sensor Problem. So, I'll have to look into that.

I noticed that when it's in P or N gear, and I press the accelerator upto 2.5-3000 RPMs), when I release it and the RPMs go down, the car starts to kindda shake (oscillate) and keeps doing it until it reaches about 750Rpm.

Another thing, I noticed white smoke coming from the tailpipe (it doesn't flow constantly, but rather "pulses"). It wasn't there when I bought the car 2 weeks ago.

Also, I don't know if it's related, but when I put new gas in it, the fuel level arrow goes up very slowly (it took it about 3 minutes to stabilize).

Sorry for a long post, but I just wanted to explain the problem.

Car specs:
Nissan Altima 94, auto, ~160,000km.

Thank you ALOT for your answer and your time,
Alex
p.s. I'm a DIY kindda guy and I don't mind getting dirty


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## WantedMobster (Oct 29, 2004)

*knock sendor*

I think all altimas get the knock sensor problem, my car has that problem. Have u tried changes plugs and such? and what kinda of gas do u use? The company, octane that sorda stuff.


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## A_L_E_X1 (Nov 5, 2004)

I'll try to see (and I hope that's the case) if the wires to the knock sensor are bad, otherwise, another 150$?

I use the regular gas (the cheapest of the three...you got the supreme, then the Plus and then the Regular, I use the Regular).

Also, I don't really choose where to fill up, whatever is near when I'm driving (it can be Shell, Petro Canada, or some independent station).

Thanks for the suggestion about plugs, I'll have to look into that too.

I just want to do everything possible before spending $$$, more important, I want to know what's wrong and not just go to the mechanic saying: Something's wrong, fix it; but rather: I want my this or that changed...

Alex


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## WantedMobster (Oct 29, 2004)

*injectors*

One of your injectors is probably giving u to much fuel


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## A_L_E_X1 (Nov 5, 2004)

Really? How I can test that?

Thanks,
Alex


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## pazuso (Oct 26, 2004)

have u tried checking out the timing? maybe u can retard the timing a little bit, say like 1-2 degrees.

ask ur local mechanic who's got a timing light gadget


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## A_L_E_X1 (Nov 5, 2004)

Thanks, pazuso, I'll do that.

This thing bothers me though, why does it stall when it's hot? Or maybe that's just a coincidence? Because the temperature sensor's gauge is in the middle of the scale, which, in my opinion, means that the engine doesn't overheat.

Alex


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## pazuso (Oct 26, 2004)

hmm, stalls when hot? thats bad i guess :-(
i once overheated my '96 sss (rad fans dont run when my aircon is off), but it didnt stall though...


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