1990 Oldsmobile Cutlass engine lurching

Tiny
KINNUF
  • MEMBER
  • 1990 OLDSMOBILE CUTLASS
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 180,000 MILES
About 1 month ago we noticed that the engine would lurch forward when we went to stop. At first it did it when it got around 22mph then it went to 13mph. It is scary when it happens. It also lurches when you move the shift lever from park to drive and from drive to park. We changed the tranny mount and the front motor mount and the two dog bones in front but are still having the same issue. Why would the engine lurch forward so much? I don't know what eles to try.
Thursday, August 14th, 2008 AT 10:59 AM

7 Replies

Tiny
MASTERTECHTIM
  • MECHANIC
  • 4,750 POSTS
Does this happen when coming to a stop, the vehicle jerks violently then stalls then when it restarts its fine until you put it in gear then it lurches real hard again?
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Thursday, August 14th, 2008 AT 8:54 PM
Tiny
KINNUF
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No it does not stall the engine itself actually moves up and forward when we slow down or move the shift lever. If you watch the engine the back of it moves up and forward causeing the dog bones to push up, then when you put it back into park the engines moves down, but it never stalls it does this when diving too, when the engine shifts down to the lowest gear it happens
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Friday, August 15th, 2008 AT 8:02 AM
Tiny
MASTERTECHTIM
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Sounds like the front lower engine mount is broken. Open hood and have someone put foot on brake then put in drive and slightly give it gas and you should see the engine mount seperate. The mount that seperates is the one that needs replacing.
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Friday, August 15th, 2008 AT 3:28 PM
Tiny
KINNUF
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  • 5 POSTS
Sorry your answer didn't help as I said in the first question all the mounts were just changed and the engine is still lurching.
This engine is able to pull forward so you can work on the backside of it. Even after changing the mounts the engine jumps up on the backside when you put it into gear and when you slow down.

Could it be the idle? Or the transmission?
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Monday, August 18th, 2008 AT 9:17 AM
Tiny
MASTERTECHTIM
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I assumed the idle was not the issue due to your complaint. But of course if the idle is too high then the engine will jump when putting in gear with new engine mounts. If the idle is not too high I swill suspect something wrong with engine mounts, or possible engine cradle mounts
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Tuesday, August 19th, 2008 AT 6:30 AM
Tiny
KINNUF
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  • 5 POSTS
Where would the cradle mounts or bolts be located?

In 2000 there was a recall on this vehicle for the engine cradle bolts pulling through the retainers. The front of the cradle would no longer be supported at the mounting locations.

The book doesn't show where these are.
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Tuesday, August 19th, 2008 AT 12:27 PM
Tiny
MASTERTECHTIM
  • MECHANIC
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Look underneath front of vehicle and the big metal frame that the engine is bolted to has 4 bolts, one on each corner, they should have big washers about 3 inches in diameter. Look to see if the bolts pulled through.
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Tuesday, August 19th, 2008 AT 7:17 PM

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