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Car hesitates when accelerating, is the EGR (exhaust gas recirculation) to blame?

edited January 2012 in Repair and Maintenance
I have a 1999 Toyota Camry (4-cylinder). When I step on the accelerator, it hesitates for a moment before accelerating. Once it finally does kick in, it isn't jerky but fairly smooth, just takes a while before it will go. Other times, when I accelerate, and the car is actually moving, I feel as though the RPMs are higher than they should be considering the (slow) speed that I'm going. These problems have increased quite a bit over the past few weeks. Prior to this, my check engine light came on. An autozone employee checked the code related to the light and said I have a faulty EGR. He didn't seem to know whether or not this would be at all related to my acceleration problem. Someone else suggested that an EGR's importance is more environmental than functional. While I'm all for "being green"...can only afford one problem at a time, and the acceleration problem comes first.

1. Any idea if the two are connected, and if not, what my acceleration problem might be?
2. How critical is a properly working EGR anyhow?

Edited: The actual code according to autozone was EGR P0401

Comments

  • It's possible an EGR fault could cause this problem but my feeling is that the hesitation is due to something else. It might also depend on exactly what EGR code is present as there are a number of them.

    A hesistation could be caused by a general state of tune problem, vacuum leak (EGR is a vacuum leak of sorts), TPS switch problem, MAF sensor, etc, etc. This could also be caused by a transmission fault based on the comment about slow speed and high RPMs.

    The EGR is an emissions device that controls NOX and is not something you would physically notice. The EGR also controls combustion chamber temperatures and this is critical. If you hear a rattle on acceleration that sounds like a rock in a can then the EGR is probably the cause of this. If it's bad enough and left unattended it can be engine damaging. If there is no rattle on hard acceleration when the engine is fully warmed up then odds are it's working ok.
  • When is the last time this car went in front of an actual mechanic? Where is it in terms of maintenance? Spark plugs? Wires? Filters? Transmission service?

    As ok4450 implied there are lots and lots of possibilities, including even that you're having a transmission problem. This is a reason to just get it in the hands of a mechanic - I think someone will have to drive it.

    I'd say that with the code now supplied, this is probably not your EGR system. The P0401 is for insufficient flow. If the EGR was making the car stumble it would be from excessive flow.
  • I'm absolutely in agreement with OK445o and with Cig, as I almost always am.

    You should know too that the code suggests a carbon buildup in the EGR valve or the orafice that it feeds eth exhaust gas through (and into the intake). It should be very easy to clean out.

    Regarding the operation problem, perhaps the best place to start is with the basics. Any good shop should be able to look at the ignition pulses with a scope, as well as look at other sensor signals and operation, and that might be the best place to start. Of course, the most basic of basics is maintenance. I gotta tell you that on that vehicle, if you're still on the original sparkplugs and you're over 60,000 miles new plugs might be all you need. Those motors do tend to be sensitive to eroding electrodes. Filters are cheap to replace too, and if you're on the original..............well, you can guess the rest.
  • I would start with the least expensive and basic things.
    First get up to date with maintenance called for in the Owners Manual.
    Next, get the MAF sensor cleaned.
    Get the valve lash checked, if applicable.
    Get the compression tested.
  • Your EGR valve probably is opened by a vacuum. If the vacuum line between the intake manifold and the
    EGR valve were to be leaking, it would cause both the driveability problems and the P0401 code. First, inspect or replace that line. A vacuum leak could also affect the shift points on the transmission.
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