[Aviation005]

So I have noticed that my car runs much better when the engine is cold. When i hit the gas there is zero delay and tons of power.

but once the engine reaches operating temp, the engine has a hard time it seems. It does not revv up as easily. When im in autostick 3d gear has a hard time revving up into the power band unless i mash the pedal down....

anyone know how to fix whats going wrong??


the car still runs great when hot, but MUCH better when cold....

[yiranhu]

COLD air intake?

I have experienced the same thing. My conjecture is that it is the fuel pump being a little weak when hot... but don't quote me on this.

[Aviation005]

Yes i do have a cold air intake!

so anyone else have any ideas as to why this is happening???

I dont think its the fuel punp for some reason.

[93'TrepFTW]

Colder Air is denser, means more power.


Also, When cold the computer is in a cycle where it has set tables for fuel trim.

When it gets warm adjusts the tables by the O2 sensors. So maybe try looking into getting some replacement O2.


And or, Intake gaskets can also be a related issue.

[tecate85]

93 trepftw you're right.

When you start the engine, the engine don't use the O2, use a pre-programmed program to warm the engine. and when it's warm the engine use the O2 sensor to inject the fuel.

if you feel a smoother engine when cold, maybe the o2 are ok maybe not. But this is because the engine stay a little high rpm.. for example 750 (when normal is 650 in my case)

that's why you feel a better "engine" in cold temp

[Charles_Scott]

Could always do a basic tune up... Replace the filters, (oil, fuel, oil), replace the plugs/wires, and do a seafoam treatment on the intake... Just to rule that sort of junk out. :-p

[Miscreation]

Is this even a topic to discuss lol jk. The air is just flowing so smoothly through the throttle body and nothing is stopping the dense cold air internal combustion. Don't always Full throttle when engine just started up, because you might crack a block, or spin a bearing, or jump a belt. Buts its always fun to do it. Cold air intakes dont always get you the power you think your gonna have when you install, you might even feel the same torque. * Not hating on Intakes though! *

[Strongt]

I'm thinking you have some worn O2 sensors. Not shot to the point of setting off the CEL, but just lazy.

[Aviation005]

Hello again. I am going to explain my problem a little more.. I think it may be a transmission problem actually.

Whenever the car is cold it shifts and revvs up perfectly. Once the car reaches operating temp 3d and 4th gear have problems getting into the power band. at full throttle in 3rd gear the car cant rev past 3500.. the RPM will drop about 200 and my steering wheel will have a quick shake. the RPM needle just gets stuck there until the speed increases allowing it to rev higher. When I let off the gas the steering wheel shakes also. (Front end parts are PERFECT all new) it is either the engine or the tranny causing the problem. Shifts into 3rd or 4th are sometimes rough and can be felt easily.. (tranny fluid is good and full).

So what does everyone think about this? Could it still be faulty O2 sensors?

[Charles_Scott]

I honestly think it can be the transmission, as they can cause your engine to act odd at times with RPM's.

[Aviation005]

Yeah its deff the tranny. Fluid level is actually really high. doubt it has been changed since 1997 lol.... Whats the best thing to have done?

Im thinking a fluid/filter change??

[blue_02]

if you're already having trani problems a fluid flush will most likely just make it worse

[Charles_Scott]

What ever you do, don't do a flush. The best thing to ATTEMPT at this point is to drop the transmission pan, clean it out, and pull the filter off, there will be an o-ring on the end of the filter that goes up inside the transmission, don't loose that, if you loose it, deff say good bye transmission. Once drained, put new filter in, and fill it up with ATF4, let it run for a little while, drive it a mile or so, and check fluids, remember, there will be ~3 or 4 quarts of the old stuff still in there because of the torque converter.

Also, input/output sensors are some common failures with the transmission.

[Aviation005]

Hey so yeah, whenever im in 3rd or 4th gear when i release the gas pedal, I get a small shake. It can be felt in the pedal, and in the steering wheel.. Its only in 3rd or 4th gear though..... and when i press the pedal in it will revv up a little, then struggle while dropping 200 RPM, after that drop it runs fine.. im confused..

If anyone can diagnose this problem without me having a shop do it you would save me $ which I dont have to begin with. Im hoping its something simple!

[Charles_Scott]

I had a similar issue, was the solenoid pack going out, and my fluid change was to late to save what life was left....