'93 Corvette Lagging
Thread Starter
Advanced
Joined: Aug 2012
Posts: 59
Likes: 0
From: Seattle WA
Vacuum steady at about 18 at idle. When given gas goes down to about 15 and holds there. If I snap open the throttle, it increases for a second, then goes down to 15 for a second then settles back at 18.
Thanks,
Richard
Thanks,
Richard
Melting Slicks
Joined: Aug 2008
Posts: 2,082
Likes: 50
From: Palmdale CA
OK, so it sounds like you have steady Vacuum at the fuel pressure regulator Vacuum hose. Yet when you connect up, the fuel pressure becomes un-steady at a lower pressure. This might be a good time to change the fuel filter and retest the fuel pressure again afterwards..
I'll find some time in the next few days, and take a look at my FSM.
I'll find some time in the next few days, and take a look at my FSM.
Thread Starter
Advanced
Joined: Aug 2012
Posts: 59
Likes: 0
From: Seattle WA
I finally got some time away from working on the house to work on the car. I got the fuel filter all changed out, and it had no effect. Actually I started to do it myself, and eventually decide that it was more trouble than it was worth so I brought it to Jiffy Lube and they only charged $20 to replace it as I brought the filter. Well worth the time saved.
Anyway, there was no change. Still lags in 4th gear, and in 6th under say 3000-3500 RPM . Also having acceleration falls off above 4500...still constant, just less pull.
I'm also now having an issue when I start the car and either back up then stop, or pull forward then stop the car really wants to die. If I don't give it gas it will struggle for 5ish seconds and eventually die. If I give it gas whether in gear or neutral it is fine. This only happens the first minute or so of driving when cold.
Just thought of something else. I sporadically get an EGR check engine code. Could this have anything to do with the issue? I also have alot of exhaust popping when decelerating which I have assumed is either the EGR or an exhaust leak that I haven't found somewhere.
Any other ideas?
Thanks,
Richard
Anyway, there was no change. Still lags in 4th gear, and in 6th under say 3000-3500 RPM . Also having acceleration falls off above 4500...still constant, just less pull.
I'm also now having an issue when I start the car and either back up then stop, or pull forward then stop the car really wants to die. If I don't give it gas it will struggle for 5ish seconds and eventually die. If I give it gas whether in gear or neutral it is fine. This only happens the first minute or so of driving when cold.
Just thought of something else. I sporadically get an EGR check engine code. Could this have anything to do with the issue? I also have alot of exhaust popping when decelerating which I have assumed is either the EGR or an exhaust leak that I haven't found somewhere.
Any other ideas?
Thanks,
Richard
Last edited by rjschwar; Mar 13, 2013 at 12:23 PM.
Racer
Joined: Oct 2010
Posts: 257
Likes: 7
From: Haslet texas
I will take a look at the EGR Valve. You can replace it, clean it, or delete it all together with a TPiS block off plate. Valve could be stuck in the open position, causing it to have a vaccum leak. You are already getting a EGR code, so I would give that a look, especially if it is stock and has not been touched since 1993.
-Ryan M.
-Ryan M.
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Thread Starter
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Joined: Aug 2012
Posts: 59
Likes: 0
From: Seattle WA
I pulled the EGR valve. It didn't appear to have alot of buildup, but I cleaned what I could, and made sure it opened and closed. I can reach in and push it open at idle and cause the engine to run really rough/die, so it doesn't appear it was stuck open. Still getting the lagging. I haven't yet gotten an EGR code but if I do I guess my next step would be to replace the valve? Should I test the solenoid somehow? What else could I look at?
Thanks,
Richard
Thanks,
Richard