1990 Chevy Lumina lunges

Tiny
SUSIESUQ
  • MEMBER
  • 1990 CHEVROLET LUMINA
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 200,000 MILES
After driving my car for 30- 45 minutes going appox. 50 -60 miles per hour, when I approach a stop sign, the car does not want to stop, it lunges forward and if I force it to stop it will stall. It started this last year and I thought it was the cruise control acting up so I disconnected it and drove 3000 on a trip and never had an incident. Now it is doing it again. Please tell me what this could be.
Wednesday, April 1st, 2009 AT 4:10 PM

6 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Has the check engine light ever come on? Have you ever checked for a plugged catylatic converter?
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Saturday, April 25th, 2009 AT 11:26 PM
Tiny
SUSIESUQ
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  • 4 POSTS
The engine light has never come on. If it was the catylatic converter, would it stop for a year and then start again? My son-in-law thought it might be the throttle position censor but said it would not start and then stop, it would just go out altogether. It seem that it is getting too strong of a gas mixture, so do you think it could be a decrease in air, which could be the catylatic converter, or could it be the air filter? If I remember correctly I had a new air filter put in before the trip, at the same time I disconnected the cruise control. Maybe I should start there? I just know it could be dangerous traveling so far from home again. Thank you for your response.
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Saturday, April 25th, 2009 AT 11:48 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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I would think a sensor would have set the check engine light. As far as the converter, I have seen them come apart inside and cause trouble randomly. If the guts are loose, it could be fine one minute then plug the next. Have you ever checked fuel pump pressure?
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Saturday, April 25th, 2009 AT 11:58 PM
Tiny
SUSIESUQ
  • MEMBER
  • 4 POSTS
No, I haven't had the fuel pump pressure checked, have no clue how to do that myself. I will check on the converter though, it would be an easy fix if that is the problem. It's weird though, cause it doesn't do this until the car is running at least a half hour, seems like it would do it all the time if it were the converter. And as long as I don't have to stop, it runs fine for hours, it's just when I need to stop, it's like it has a mind of it's own and just wants to keep going and pays me back by stalling :).
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Sunday, April 26th, 2009 AT 1:14 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
You are most likely right, but if a converter is loose inside, it can move around and cause problems.

Let me understand. Are you saying when you slow down, the engine tries to keep pulling and then die?
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Sunday, April 26th, 2009 AT 11:58 AM
Tiny
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  • 4 POSTS
Yes, when I want to slow down to stop, the car wants to keep going, lurching forward. When I force it to stop it stalls and then doesn't want to start.
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Sunday, April 26th, 2009 AT 2:53 PM

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