Help diagnosing stumbling LT1...
Help diagnosing stumbling LT1... My mother has a 94 Roadmaster with a LT1 under the hood. It has run pretty well its life until recently when it started stumbling under load when you first go to roll it off the line. I can rev it in park or neutral and it will be as smooth as it could be but if I put it in drive or reverse, it wants to stall out when you start it rolling away from a stop.
*I have replaced the fuel pump, fuel filter and fuel pressure regulator
*I have run a compression test and it is fine
*I have checked for vacuum line issues and found none
*I have changed out all 8 spark plugs (I will post a pic of the plugs that were removed shortly)
I am running out of ideas to look. I have read that maybe a bad EGR can cause issues like this. I know the car is on the original opti since I have done all the work to it for quite a while and it never acted up before now in the entire time she has had it.
Anybody else have any ideas or things to test out? The only ideas I have left are:
*manifold leak somewhere
*failing optispark
*faulty injector(s)
*EGR issue
Thoughts?
*I have replaced the fuel pump, fuel filter and fuel pressure regulator
*I have run a compression test and it is fine
*I have checked for vacuum line issues and found none
*I have changed out all 8 spark plugs (I will post a pic of the plugs that were removed shortly)
I am running out of ideas to look. I have read that maybe a bad EGR can cause issues like this. I know the car is on the original opti since I have done all the work to it for quite a while and it never acted up before now in the entire time she has had it.
Anybody else have any ideas or things to test out? The only ideas I have left are:
*manifold leak somewhere
*failing optispark
*faulty injector(s)
*EGR issue
Thoughts?
Last edited by Project10AE; Dec 3, 2012 at 08:54 PM.
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Joined: Oct 2006
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From: POULSBO WA.
Do a live scan of the datastream. Look at the tps, should be around .65-.69 @0%. slack in the cable can have some effect as well. Mine was at .62 and i developed a slight stumble because the throttle blades were opening before the computer saw 1%+ so it saw a lean condition, so i adjusteded upward. Is the car tuned? Adding timing can help as well.
