99 Camry Hesitation while maintaining speed

On Jan 21, 10:30 am, wrote:
> On Jan 20, 11:17 am, Tom M wrote:
>
> > Hello:
> > My '99 Camry V6 (222,000 miles) just developed a problem where it
> > hesitates / surges while trying to maintain a constant speed, most
> > notably around 40mph.  While coasting or accelerating everything seems
> > fine.  No service codes are tripped.  Does anyone have any ideas as to
> > what I should check / monitor?
>
> > Thanks,
> > Tom
>
> EGR valve, fuel filter, throttle body butterfly valve off the top of
> my head
>
> Michael


I just thought of a couple more things: fuel pump could be going bad,
or your fuel injectors might be dirty. Try putting a bottle of Red
Line fuel injector cleaner in your gas tank. About $7 at Pep Boys.
It's the easiest fix for now. Otherwise just fill up with Chevron/
Techron and see how it goes

Michael
 >> Stay informed about: 99 Camry Hesitation while maintaining speed 

> > EGR valve, fuel filter, throttle body butterfly valve off the top of
> > my head
>
> > Michael
>
> I just thought of a couple more things:  fuel pump could be going bad,
> or your fuel injectors might be dirty.  Try putting a bottle of Red
> Line fuel injector cleaner in your gas tank.  About $7 at Pep Boys.
> It's the easiest fix for now.  Otherwise just fill up with Chevron/
> Techron and see how it goes
>
> Michael-

Thank you Michael. I very much appreciate your response. I bought a
new gas filter tonight and will put it in tomorrow along with some
injector cleaner. That's probably the best / easiest place to start.
I did take a look at the throttle body butterfly valve and it is a bit
dirty but seemed to work OK. I'll clean that up too. I'll post if I
have any success. Thanks.
- Tom -
 >> Stay informed about: 99 Camry Hesitation while maintaining speed 

Tom M wrote:
I bought a
> new gas filter tonight and will put it in tomorrow along with some
> injector cleaner. That's probably the best / easiest place to start.
> I did take a look at the throttle body butterfly valve and it is a bit
> dirty but seemed to work OK. I'll clean that up too.
=======
17mm crow foot wrench seems to work best at breaking loose the lower
fitting on the fuel filter without damaging the line, but your initial
description of surging at steady speed but not under acceleration
makes me think fuel flow is OK.
Could be EGR valve operating improperly though.
When removing the throttle body for cleaning, according to the factory
service manual, there are three progressively smaller holes or ports
that are revealed as the butterfly valve opens. You will see vacuum
lines from these openings in the throttle body connected by vacuum
hoses to the EGR modulator which operates the EGR valve.
Once the throttle body is off, you clean the holes with solvent and
blow them out with compressed air.
The smallest of the holes is quite tiny, and fairly easily blocked.
If you remove the throttle body there are also procedures for setting
the -- sorry, forgot what they call it -- the circular variable
resistor on the side that signals the ECM computer regarding throttle
opening. You check for continuity off idle with a thickness gauge.
Found mine was out of adjustment. Then there is another setting for
the vacuum line coming off the other side. You disconnect the line,
and adjust a set screw for idle speed when the throttle is released
abruptly, like when coming up to a stop.
See:
http://www.turboninjas.com/camry/
Should be in the engine section.
I bought the paper manuals on eBay. Very useful to have at hand when
performing procedures, as you can follow step by step, and observe
torque values also.
 >> Stay informed about: 99 Camry Hesitation while maintaining speed 

Michael , Daniel

Thanks very much for your help. Luckily the car threw a code last
night (P1410 - EGR Sensor) that helped narrow it down. You guys were
right - EGR system. Got a sensor from Toyota ($37), 30 seconds to
install, and I'm good to go. Ordinarily I would have spent more time
troubleshooting the system before deciding on changing the sensor but
it was cheap enough and it was darn cold out so I took the easy way
out. Took a chance that the sensor was at fault. The car now runs
smoothly through that 38-44 mph range that caused me the problem
before. Thanks again.

Tom
 >> Stay informed about: 99 Camry Hesitation while maintaining speed