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So, I have an 82 vette, and the idle is shaky. Now what I mean by this, at lower rpms (about 600-700 and the car is warmer), the car has a somewhat off rhythm shake like a misfire. However small, it still isn't happy. I’m really puzzled on what I should do next. I’ve done things Like the IAC's and set them by driving 35mph, I’ve replaced the EGR and rebuilt the TBI. Checked vacuum and replaces CTS and MAP censors. Redone the cap and rotor and new plugs and wires. New pump and filter and the list go on.
Someone told me that the EGR solenoid is having and internal leak. Not sure where that is, and I haven’t really found any parts to go with the assessment. Does anyone know if this would be an issue? and how to test and find the parts for it?
EGR is not supposed to come into play until the engine has warmed up. That being said, if you think it's that, just disconnect the hose going to it, and plug it. If it gets better then it could be the solenoid but first thing first, Do you have a scan tool to monitor fuel delivery and oxygen sensor output?
From: At my Bar drinking and wrenching in Lafayette Colorado
I've had 2 1982 Vettes. Both had a "slight misfire" that was most noticeable at idle. It turned out, both cars had cams with flat, or near-flat, lobes on one or more cylinders. Apparently, they had a problem with some "soft cams" in the '82 engines. Before chasing ghosts in the ignition and fuel systems, you might want to pop the valve covers off and just do a visual check on your rocker arm movements to make sure you don't have some flat cam lobes.
Lars
EGR is not supposed to come into play until the engine has warmed up. That being said, if you think it's that, just disconnect the hose going to it, and plug it. If it gets better then it could be the solenoid but first thing first, Do you have a scan tool to monitor fuel delivery and oxygen sensor output?
so I forgot to iterate that this condition that I’m having is only really when it is warm or at least that’s when it’s the most noticeable. When the car is warming up on a cold day, the car idles very very well. As for the scan tool, I do not but I will get one asap
How many miles on this car? Also, when it acts up, does your idle appear to be higher than normal?
The car has around 80,000 miles in the car and the idle is around 700 up or down. But hangs around 600-700 when warm. Which is fairly normal for the car.
The car has around 80,000 miles in the car and the idle is around 700 up or down. But hangs around 600-700 when warm. Which is fairly normal for the car.
I'd get a scan tool hooked up to monitor oxygen sensor output. If you're not sure how to read that data, let me know, and I'll explain it to you.
I'd get a scan tool hooked up to monitor oxygen sensor output. If you're not sure how to read that data, let me know, and I'll explain it to you.
I have the exact problem, replaced the O2 sensor and exactly the same, no change to the idle.I have 23000 miles, runs fine until it warms up and idles around 700 in park and 600 in drive. Idles rough when in drive more than in park.
Last edited by DarrellD23; Nov 28, 2021 at 03:44 PM.
I just wonder how some of you people haven't seen or heard the car run, and come to these conclusions without any testing. Just because it happened to your car, doesn't mean it applies in this case.
I have the exact problem, replaced the O2 sensor and exactly the same, no change to the idle.I have 23000 miles, runs fine until it warms up and idles around 600
Yes, I tried it as well and smoothed out the upper rpm’s, but not lower.
Is it safe to assume the issue was present before you changed the plugs and wires, which is what prompted you to replace those to begin with?
Any chance that the wires on #5 and #7 are swapped? If they were wrong before, and you replaced them being careful to put back exactly what you started with, the symptoms do not go away.
Does it drive fine at all other speeds and you only feel this effect during idle only?
Is it safe to assume the issue was present before you changed the plugs and wires, which is what prompted you to replace those to begin with?
Any chance that the wires on #5 and #7 are swapped? If they were wrong before, and you replaced them being careful to put back exactly what you started with, the symptoms do not go away.
Does it drive fine at all other speeds and you only feel this effect during idle only?
The plug wires are correct as I have looked at diagrams of both the distributor cap and the firing order. This coupled with the taping and number of the wires. As for this shaky running. It is only with the idle. Now something to note which may or may not be relevant, holding a slight throttle, the car Boggs and drops rpm’s slightly and runs rough. Like it doesn’t like to be at about 10% throttle. Could that be a symptom of something with the idle? I have replaced the coil.
Have you run a Propane sniffer around the plenum to top plate gasket? This bad boy turns into a rock and can leak after 20 years...much less 40. It will cause an erratic idle.....
Have you run a Propane sniffer around the plenum to top plate gasket? This bad boy turns into a rock and can leak after 20 years...much less 40. It will cause an erratic idle.....
Evap smoke machine is the way to go for finding vacuum leaks. I can't emphasize this enough. Especially anyone who owns a car with pneumatic hideaway headlights. I was able to find within a few minutes a leaking headlight relay, a hose, EGR solenoid, and both IAC valves. You get them inexpensively on Evil bay.
Evap smoke machine is the way to go for finding vacuum leaks. I can't emphasize this enough. Especially anyone who owns a car with pneumatic hideaway headlights. I was able to find within a few minutes a leaking headlight relay, a hose, EGR solenoid, and both IAC valves. You get them inexpensively on Evil bay.
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82 Vette Shaky Idle
