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Diagnose my problem please

S

skeelo58

New member
For the last couple years, my 02 Coupe has been suffering from a strange "surging" problem (I will try explain).

Ya see, when the temp is fairly cool (60 degrees or cooler), the car will accelerate at a constant pace. However, once it gets hot out (75 or above), I can put my foot on the gas, and it will accelerate much slower than normal for about 2 or 3 seconds, and then all of a sudden it will have a sudden boost in acceleration, even though my foot hasn't applied any extra pressure to the gas pedal.

I don't know if that is technically surging, but it is very strange. Can someone please explain to me why this happens ONLY when it is hot out, and never happens when it is cool out?
 


Sounds like a local GTP guy here...if there is well over 100K on your car I'd be willing to bet money on it the Torque converter isn't locking until you feel that extra pull...and temperature related would make sense too.
 
My first question is how many miles on the car?

I'm wondering if the Intake Air Temp (IAT) sensor is going bad. Could be getting heat-soaked, then when you throttle it the air starts rushing in, cools the sensor, and your timing gets restored. It definitely sounds like your timing is pulled and then you get it back.
 
GeosGP said:
My first question is how many miles on the car?

I'm wondering if the Intake Air Temp (IAT) sensor is going bad. Could be getting heat-soaked, then when you throttle it the air starts rushing in, cools the sensor, and your timing gets restored. It definitely sounds like your timing is pulled and then you get it back.
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The car has 119k on it.

Is this a problem I can fix on my own? I do not want to take apart the engine or anything, so I'm hoping that by intake, you mean it is located close to the air intake, correct?

Warbeaver: I had my catalytic converter replaced 3 years ago, and they replaced the fuel filter at that time. I have occassionaly put in fuel injector cleaner in my gas tank from time to time, but that doesn't seem to help at all.
 
skeelo58 said:
The car has 119k on it.

Is this a problem I can fix on my own? I do not want to take apart the engine or anything, so I'm hoping that by intake, you mean it is located close to the air intake, correct?

Warbeaver: I had my catalytic converter replaced 3 years ago, and they replaced the fuel filter at that time. I have occassionaly put in fuel injector cleaner in my gas tank from time to time, but that doesn't seem to help at all.
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Yes, the IAT is located on the intake tube between the airbox and throttlebody. Or it may be part of the MAF assembly.

I know that BlueGTP91 mentioned it might be your converter checking out... how is your trans fluid doing? Is it red? Does it smells burnt?
 


GeosGP said:
Yes, the IAT is located on the intake tube between the airbox and throttlebody. Or it may be part of the MAF assembly.

I know that BlueGTP91 mentioned it might be your converter checking out... how is your trans fluid doing? Is it red? Does it smells burnt?
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I haven't checked the tranny fluid, but I don't foresee that being the culprit. I had the tranny fluid flushed about a year ago or so. I don't think this is a transmission problem at all. It's not like it just suddenly grabs, it's just like it gets a sudden boost of acceleration, almost like more air is being thrown into the engine, so I think the IAT solution makes more sense than the Torque converter.

One more thing I should mention.... Normally it happens from a stop, ie 0-35, and the boost will kick in at about 20 mph or so. But, it also does happen when I'm already going about 40, and then I floor it. The car will be slow to accelerate for a couple seconds, until it finally decides to actually accelerate to WOT.... And since, like I said, this only happens when it is relatively warm out, it does kind of make sense about the air intake thing. If it was a torque converter problem, I would assume that it would happen all the time, not just when it is hot outside.
 
No mods whatsoever. The only thing I've ever done to the engine is swapped the stock paper air filter out for a Fram Air Hog filter 5 years ago. I've put on 42k miles with that filter, but it hasn't gotten particularly dirty from what I can tell.
 
The reason that I asked about the air filter is that sometimes the K&N oil will end up on the MAF wires and cause incorrect readings. Was wondering if that could be part of the issue here.

Do you know someone else with a car like yours so you could swap out the MAF/IAT and test it out?
 
Unfortunately I don't know anyone else with a GP. For some reason, all my friends seem to "know someone that had bad luck with Pontiac", so they all absolutely REFUSE to ever buy a Pontiac.

Funny thing is, the one friend of mine that particularly has it out for Pontiac, he has a Toyota Camry Solara that he bought about the same time I got my GP. He has spent roughly 4000 dollars over the last few years fixing various problems with his car, and now the car body has some serious rust problems as well. But yet, he doesn't seem to think that Toyota suffers from any quality problems, just Pontiac.

But I digress..... I am actually leaving for Basic Training for the Army next week, so this problem will probably have to wait until I come back. It's not really a "problem" per se, just an odd occurrance that I would like to take care of before any other problems happen....
 


Oh, then punt on this car stuff. Spend time with your family and friends now.

Good luck in Basic. What MOS?
 
Toyota. Going forward. WOT with zero user control.

NA, Toyota doesn't have any problems at all. everything is great.

Honda is the same story. all of the thousands of transmission and torque converter failures were made up. they also have zero problems.

The real fact is. It doesn't matter if a car says Pontiac, Honda, Toyota, Ford or Hoyt Clagwell. They ALL have issues from time to time.
 
GeosGP said:
Oh, then punt on this car stuff. Spend time with your family and friends now.

Good luck in Basic. What MOS?
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My MOS is Intel Analyst. It requires a Top Secret security clearance :) Maybe now I can finally find out if aliens landed at Roswell! Hahaha.
 
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