91 3VZE stock configuration everywhere, Automatic trans. A few days ago the engine starting stumbling pretty bad when you give it gas, I first thought it was because it was cold, but then I noticed the temperature was in the normal range as it had been idling a while. It has gotten worse and when starting across a street or something you don't know if it is going to fall on its face or go. I have been tinkering with it and notice that when I crack the throttle open a little while working under the hood, it starts to miss real bad just above idle. I fisrt thought throttle position sensor so I replaced that with a spare I had but it still does the same thing. If I open the throttle up alot, the engine will take off and run. It almost feels like it develops a real bad vacuum leak or something when you open the throttle, it almost dies sometimes. What gets me is that it will just sit there and run rough and not clear up when you hold it open a little.

Any thoughts? I have not had anything quite like this before. maybe distributor/vaccum advance malfunction or module or?????
Cheers!

Kris

 

Check for codes ?
Did you adjust the TPS after you installed it ?




Fred

 

could that be the egr stuck open? if it will run fine when you open it up and it runs bad just at lower rpms then that could be something to check