strange problem with 91 MR2 , cannot determine cause

I've been to several mechanics, talked to several friends and posted on
several lists without any kind of definitive solution to my problem,
but i'll post here incase someone has seen something very similar
before.

I have a 91 Toyota MR2 (naturally aspirated) auto transmission with
~80,000mi on it. It's in very good condition for its age, with the
interior and exterior looking practically new and all original factory
parts. Basically, for a 15+ yr old car it's not too bad.

The problem started a couple months ago. I'd be driving along on the
highway and suddenly, the car would start slowing down; imperceptible
at first, but it would get hard to maintain the same speed, and more
gas would have to be given to the point where I would be slamming the
gas down to keep the same speed, and in order not to cause unknown
damage to the car i'd slow down and pull off to the side. While slowing
down I would put it in neutral and rev the engine, and it would rev
without a problem, but put gas and it would feel like it's struggling
to move. Applying the brakes made very little difference.

Pulled off to the side of the road, the car is idling ~800rpms and at a
full stop - with the transmission in drive. I learned I could press the
brakes completely several times, and then the car would creep forward.
I could then drive it like normal but the problem would eventually come
back, at first about 24 hours at a time and now more like an hour at a
time.

I had the fuel filter replaced and it made no difference. I brought it
to a Toyota dealership and they found that the brake fluid was a
milky-white consistency, and proclaimed this was the cause and please
give them $3,000 to replace all my brake parts (hoses, master cylinder,
calipers, probably brake booster too and flush the brake fluid). Since
I don't have that kind of money lying around, I want to find another
way to fix the problem without spending a whole lot. If I can do it in
stages that would be best, so if I have to spend $1500 i'd like to do
that a little bit here, a little bit there when I get the money.

I understand I should flush the brake fluid first, but what next? (I'd
also like to do the fixes myself to save on labor costs, but I am very
much a newbie, so if you happen to have the holy grail of automotive
repair manuals for beginners lying around i'd love to look at it)

I've gotten these suggestions to fix the problem: test the fuel pump's
fuel pressure while driving, replace the cat, rebuild (not replace) the
calipers, replace master cylinder/hoses/calipers, check for vacumm
leaks, replace vacumm hoses, check/replace vacumm sensor.

Pete wrote:
> I've been to several mechanics, talked to several friends and posted on
> several lists without any kind of definitive solution to my problem,
> but i'll post here incase someone has seen something very similar
> before.
>
> I have a 91 Toyota MR2 (naturally aspirated) auto transmission with
> ~80,000mi on it. It's in very good condition for its age, with the
> interior and exterior looking practically new and all original factory
> parts. Basically, for a 15+ yr old car it's not too bad.
>
> The problem started a couple months ago. I'd be driving along on the
> highway and suddenly, the car would start slowing down; imperceptible
> at first, but it would get hard to maintain the same speed, and more
> gas would have to be given to the point where I would be slamming the
> gas down to keep the same speed, and in order not to cause unknown
> damage to the car i'd slow down and pull off to the side. While slowing
> down I would put it in neutral and rev the engine, and it would rev
> without a problem, but put gas and it would feel like it's struggling
> to move. Applying the brakes made very little difference.
>
> Pulled off to the side of the road, the car is idling ~800rpms and at a
> full stop - with the transmission in drive. I learned I could press the
> brakes completely several times, and then the car would creep forward.
> I could then drive it like normal but the problem would eventually come
> back, at first about 24 hours at a time and now more like an hour at a
> time.
>
> I had the fuel filter replaced and it made no difference. I brought it
> to a Toyota dealership and they found that the brake fluid was a
> milky-white consistency, and proclaimed this was the cause and please
> give them $3,000 to replace all my brake parts (hoses, master cylinder,
> calipers, probably brake booster too and flush the brake fluid). Since
> I don't have that kind of money lying around, I want to find another
> way to fix the problem without spending a whole lot. If I can do it in
> stages that would be best, so if I have to spend $1500 i'd like to do
> that a little bit here, a little bit there when I get the money.
>
> I understand I should flush the brake fluid first, but what next? (I'd
> also like to do the fixes myself to save on labor costs, but I am very
> much a newbie, so if you happen to have the holy grail of automotive
> repair manuals for beginners lying around i'd love to look at it)
>
> I've gotten these suggestions to fix the problem: test the fuel pump's
> fuel pressure while driving, replace the cat, rebuild (not replace) the
> calipers, replace master cylinder/hoses/calipers, check for vacumm
> leaks, replace vacumm hoses, check/replace vacumm sensor.


Next time it happens make sure you have a thermometer with you and
quickly check the temperature of the brakes. It sounds like maybe the
brakes are dragging. It should be an obvious thing to find .

If you cant afford the brake job I would at least flush and refill the
brake fluid. It may only be a temporary solution but should prove the
repair.

>Applying the brakes made very little difference.

If applying the brakes makes very little difference then the brakes
must already be on.
>
> I learned I could press the
>brakes completely several times, and then the car would creep forward.
>I could then drive it like normal

Applying the brakes several times eventually releases the brake
pressure.


As the other reply states you have a brake problem. It WILL make heat
and lots of it. Check it out when it happens again. Compare the heat
difference between all wheels.

If the brakes need bleeding you could try this:
http://www.motiveproducts.com/

I would also check for excessive exhaust back pressure from a collapsed
muffler or clogged catalytic converter.See if you get a constant vacuum
at the throttle body at constant engine speed.

If you are sure the brakes are dragging here, the booster is bad, I
experienced this several times when I was with Toyota on 90-92 trucks, not
cars, but the symptoms you describe are similar, also make sure there is
free travel in the brake pedal,before the brakes start to apply. If you
remove the vacuum hose and check valve from the booster when this happens
the car should move freely if it is the booster.
"Pete" > wrote in message
ups.com...
> I've been to several mechanics, talked to several friends and posted on
> several lists without any kind of definitive solution to my problem,
> but i'll post here incase someone has seen something very similar
> before.
>
> I have a 91 Toyota MR2 (naturally aspirated) auto transmission with
> ~80,000mi on it. It's in very good condition for its age, with the
> interior and exterior looking practically new and all original factory
> parts. Basically, for a 15+ yr old car it's not too bad.
>
> The problem started a couple months ago. I'd be driving along on the
> highway and suddenly, the car would start slowing down; imperceptible
> at first, but it would get hard to maintain the same speed, and more
> gas would have to be given to the point where I would be slamming the
> gas down to keep the same speed, and in order not to cause unknown
> damage to the car i'd slow down and pull off to the side. While slowing
> down I would put it in neutral and rev the engine, and it would rev
> without a problem, but put gas and it would feel like it's struggling
> to move. Applying the brakes made very little difference.
>
> Pulled off to the side of the road, the car is idling ~800rpms and at a
> full stop - with the transmission in drive. I learned I could press the
> brakes completely several times, and then the car would creep forward.
> I could then drive it like normal but the problem would eventually come
> back, at first about 24 hours at a time and now more like an hour at a
> time.
>
> I had the fuel filter replaced and it made no difference. I brought it
> to a Toyota dealership and they found that the brake fluid was a
> milky-white consistency, and proclaimed this was the cause and please
> give them $3,000 to replace all my brake parts (hoses, master cylinder,
> calipers, probably brake booster too and flush the brake fluid). Since
> I don't have that kind of money lying around, I want to find another
> way to fix the problem without spending a whole lot. If I can do it in
> stages that would be best, so if I have to spend $1500 i'd like to do
> that a little bit here, a little bit there when I get the money.
>
> I understand I should flush the brake fluid first, but what next? (I'd
> also like to do the fixes myself to save on labor costs, but I am very
> much a newbie, so if you happen to have the holy grail of automotive
> repair manuals for beginners lying around i'd love to look at it)
>
> I've gotten these suggestions to fix the problem: test the fuel pump's
> fuel pressure while driving, replace the cat, rebuild (not replace) the
> calipers, replace master cylinder/hoses/calipers, check for vacumm
> leaks, replace vacumm hoses, check/replace vacumm sensor.
>



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Shep > wrote:
>If you are sure the brakes are dragging here, the booster is bad, I
>experienced this several times when I was with Toyota on 90-92 trucks, not
>cars, but the symptoms you describe are similar, also make sure there is
>free travel in the brake pedal,before the brakes start to apply. If you
>remove the vacuum hose and check valve from the booster when this happens
>the car should move freely if it is the booster.

I agree with the booster diagnosis. HOWEVER, you will want to change the
fluid, replace the pads and at least inspect (and probably replace) the
rotors because of the damage done to them by the dragging. On top of fixing
the booster.

Take it to someone else, and just ask what the condition of the brakes are.
If you _have_ had dragging, you'll find everything will be in pretty bad
shape.

The fluid being milky COULD be a sign that the brakes have been overheating.
It could also be an unrelated issue, especially if you aren't changing the
fluid every couple years. Either way, if it's milky, you need to change it
immediately.

Don't mess around with brakes. Lots of things on a car won't matter much
if they fail. Some things will leave you stranded when they fail. Brakes
leave you dead when they fail. Death is bad.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Also possible here someone added p/s fluid to the master you can get the
similar symptoms from that also.
"Scott Dorsey" > wrote in message
...
> Shep > wrote:
>>If you are sure the brakes are dragging here, the booster is bad, I
>>experienced this several times when I was with Toyota on 90-92 trucks, not
>>cars, but the symptoms you describe are similar, also make sure there is
>>free travel in the brake pedal,before the brakes start to apply. If you
>>remove the vacuum hose and check valve from the booster when this happens
>>the car should move freely if it is the booster.
>
> I agree with the booster diagnosis. HOWEVER, you will want to change the
> fluid, replace the pads and at least inspect (and probably replace) the
> rotors because of the damage done to them by the dragging. On top of
> fixing
> the booster.
>
> Take it to someone else, and just ask what the condition of the brakes
> are.
> If you _have_ had dragging, you'll find everything will be in pretty bad
> shape.
>
> The fluid being milky COULD be a sign that the brakes have been
> overheating.
> It could also be an unrelated issue, especially if you aren't changing the
> fluid every couple years. Either way, if it's milky, you need to change
> it
> immediately.
>
> Don't mess around with brakes. Lots of things on a car won't matter much
> if they fail. Some things will leave you stranded when they fail. Brakes
> leave you dead when they fail. Death is bad.
> --scott
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."
>



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