engine or transmision

1997 GMC SIERRA
162,000 MILES • 5.7L • V8 • 2WD • AUTOMATIC
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KENNAMETAL
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I have a check engine light on which was decoded saying it was the EGR which i replaced a few years back. my problem is that when i get up to go between 52 and 78 mph it starts to act like I get a massive miss in the engine, but quits if I gas it. I have been working on cars for years, but this is a new one. Would the EGR valve make it cut out at certain rpm or would it miss all the time? It did not do this before I replaced It last time. As bad as it shakes when it does, could there be something going on with the transmission? It seems to be shifting normally, but with that kind of vibration I would have to drop more than one cylinder.
Mar 12, 2016 at 1:06 PM
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HMAC300
  • AUTOMOTIVE REPAIR CONTRIBUTOR
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it may be sticking or the passage partially blocked, but going that speed it may be open anyhow. what is code?
Mar 12, 2016 at 1:28 PM
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KENNAMETAL
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I just took the the EGR off a couple of weeks ago and cleaned it to see if the check engine light would come off. it wasn't dirty, but the check light would stay off for a while then come back on. The code at the parts store said EGR. Sorry do not have the number.
Mar 12, 2016 at 2:36 PM
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HMAC300
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 48,601 POSTS
okay check to see if egr valve isn't on backwards as this can be done. If you are looking at the engine from the front the electrical connection should be at left. Check for soft vacuum hoses collapsing with vacuum.
Mar 12, 2016 at 3:37 PM