1991 5.7 TPI runs great when engine is cold, but not after it warms up
07-15-2014, 08:50 PM
#1
Junior Member
Thread Starter
Join Date: Jul 2014
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
1991 5.7 TPI runs great when engine is cold, but not after it warms up
Hello I hope I can get some much needed help. I rescued a 1991 Z28 1LE from a parking lot in the Bronks. Hadn't been started for 5 years. Brought it back to Kansas. Replaced the ignition and key and pumped out the old gas and put in some fresh. Started up after 4 tries 
. However ran not so hot. After some diagnostic troubleshooting I discovered that the distributor needed overhauled and some vacuum lines where bad. Fixed and then for giggles replaced the fuel filter. Then I said whey not replace the spark plugs. Done. Checked the wires they looked like new. At this point the car starts good and runs nice. However when it gets to the operating temp it runs sluggish. But when the engine is cool it will leave a nice 
. It's running on all 8 and no service light. So I said why not replace to O2. Still no change. But what is funny is after I fixed the air conditioning I noticed that when the engine was cold it would blow ice cold air. But like the throttle response it too doesn't work right when the engine warms up. The only things that I have not replaced is the egr and the egr selonoid. I believe the issue is that or maybe the 23 old injectors??? Car does not overheat. I have not checked for codes, but I know I'm not far away. Please help! 
. However ran not so hot. After some diagnostic troubleshooting I discovered that the distributor needed overhauled and some vacuum lines where bad. Fixed and then for giggles replaced the fuel filter. Then I said whey not replace the spark plugs. Done. Checked the wires they looked like new. At this point the car starts good and runs nice. However when it gets to the operating temp it runs sluggish. But when the engine is cool it will leave a nice . It's running on all 8 and no service light. So I said why not replace to O2. Still no change. But what is funny is after I fixed the air conditioning I noticed that when the engine was cold it would blow ice cold air. But like the throttle response it too doesn't work right when the engine warms up. The only things that I have not replaced is the egr and the egr selonoid. I believe the issue is that or maybe the 23 old injectors??? Car does not overheat. I have not checked for codes, but I know I'm not far away. Please help! 
07-16-2014, 05:57 PM
#2
Member
Hello I hope I can get some much needed help. I rescued a 1991 Z28 1LE from a parking lot in the Bronks. Hadn't been started for 5 years. Brought it back to Kansas. Replaced the ignition and key and pumped out the old gas and put in some fresh. Started up after 4 tries . However ran not so hot. After some diagnostic troubleshooting I discovered that the distributor needed overhauled and some vacuum lines where bad. Fixed and then for giggles replaced the fuel filter. Then I said whey not replace the spark plugs. Done. Checked the wires they looked like new. At this point the car starts good and runs nice. However when it gets to the operating temp it runs sluggish. But when the engine is cool it will leave a nice . It's running on all 8 and no service light. So I said why not replace to O2. Still no change. But what is funny is after I fixed the air conditioning I noticed that when the engine was cold it would blow ice cold air. But like the throttle response it too doesn't work right when the engine warms up. The only things that I have not replaced is the egr and the egr selonoid. I believe the issue is that or maybe the 23 old injectors??? Car does not overheat. I have not checked for codes, but I know I'm not far away. Please help!
. However ran not so hot. After some diagnostic troubleshooting I discovered that the distributor needed overhauled and some vacuum lines where bad. Fixed and then for giggles replaced the fuel filter. Then I said whey not replace the spark plugs. Done. Checked the wires they looked like new. At this point the car starts good and runs nice. However when it gets to the operating temp it runs sluggish. But when the engine is cool it will leave a nice . It's running on all 8 and no service light. So I said why not replace to O2. Still no change. But what is funny is after I fixed the air conditioning I noticed that when the engine was cold it would blow ice cold air. But like the throttle response it too doesn't work right when the engine warms up. The only things that I have not replaced is the egr and the egr selonoid. I believe the issue is that or maybe the 23 old injectors??? Car does not overheat. I have not checked for codes, but I know I'm not far away. Please help! Have you tested your injectors to see if they performing well? They could be the originals and those multi-techs do not last long.
07-16-2014, 05:58 PM
#3
Member
Good job on saving the car. Have you tested your injectors to see if they performing well? They could be the originals and those multi-techs do not last long.
07-17-2014, 03:15 PM
#4
Member
Re: 1991 5.7 TPI runs great when engine is cold, but not after it warms up
Have you tried to pull any DTC codes? This is where I would start from.
Thread
Thread Starter
Forum
Replies
Last Post