Running rough
Thread Starter
6th Gear
Joined: Mar 2017
Posts: 6
Likes: 0
Running rough
I hope somebody might give me some direction. I have a 1992 that has begun to run a little rough, and I am wondering how to fix it. Last winter (about a thousand miles ago ) it ran rough, and the check engine light came on, so I replaced the spark plugs and wires. Did not replace the optispark. The car ran better, but now it a little poochy again. No check engine light. This vette has barely been driven in the past four years ... maybe a tank of gas or so per year, so I suspect it might be some fuel turning to varnish. But I'm not sure how to diagnose something like that, if that is indeed the problem. What would a sage mechanic check first? Has anyone gone through something like this? Any help or suggestions appreciated.
Intermediate
Joined: Sep 2020
Posts: 36
Likes: 15
From: Montreal
It could be so much things. Do you have any other symptoms ? Can you describe "rough" a little more ? Can you see the engine shaking ? Is it steady shaking or irregular ? Anything unusual that you can observe will help to narrow it down to the cause. Any loss of power ?
Start with the easy things
- Vaccum to the FPR (smell of gas) ?
- Vaccum leaks ? You can use the cigar trick or the MAF cleaner trick.
- Fire from the spark plugs ?
- Noid light on the injectors ? Resistance on the injectors ?
- Gas pressure (holding and while running) ?
- Good contact between the distributor rotor and cap ? (this is something that needs to be changed once in a while in these old vehicules.)
- Air filter ? Unplug it to see the difference ?
- etc ...
Start with the easy things
- Vaccum to the FPR (smell of gas) ?
- Vaccum leaks ? You can use the cigar trick or the MAF cleaner trick.
- Fire from the spark plugs ?
- Noid light on the injectors ? Resistance on the injectors ?
- Gas pressure (holding and while running) ?
- Good contact between the distributor rotor and cap ? (this is something that needs to be changed once in a while in these old vehicules.)
- Air filter ? Unplug it to see the difference ?
- etc ...
Last edited by 87redrocket; Sep 16, 2020 at 04:33 PM.
Thread Starter
6th Gear
Joined: Mar 2017
Posts: 6
Likes: 0
Thanks redrocket.
I have not driven it for a couple of weeks, so I just took the car out for ride, to get a feel for the way it's running. I did my normal twisty route, and then got it up to highway speed on the way home, about 20 miles total, and it ran fine. Did not seem to miss a lick.
One thing I did not mention: my wife put some regular gas in the car, a tank before the current one. After she did it, I put in some octane booster. Ran it down to about a quarter tank and refilled with premium. I never really noticed any issues, but now I wonder if there is a residual amount of regular gas that caused the problem a couple of weeks ago.
I need to be better about driving it regularly and keeping fresh gas in it. I'm going to keep your list of ideas in case it starts acting up again.
thanks again
I have not driven it for a couple of weeks, so I just took the car out for ride, to get a feel for the way it's running. I did my normal twisty route, and then got it up to highway speed on the way home, about 20 miles total, and it ran fine. Did not seem to miss a lick.
One thing I did not mention: my wife put some regular gas in the car, a tank before the current one. After she did it, I put in some octane booster. Ran it down to about a quarter tank and refilled with premium. I never really noticed any issues, but now I wonder if there is a residual amount of regular gas that caused the problem a couple of weeks ago.
I need to be better about driving it regularly and keeping fresh gas in it. I'm going to keep your list of ideas in case it starts acting up again.
thanks again
Team Owner
Joined: Jul 2004
Posts: 28,470
Likes: 3,289
From: Hartford WI
Thanks redrocket.
I have not driven it for a couple of weeks, so I just took the car out for ride, to get a feel for the way it's running. I did my normal twisty route, and then got it up to highway speed on the way home, about 20 miles total, and it ran fine. Did not seem to miss a lick.
One thing I did not mention: my wife put some regular gas in the car, a tank before the current one. After she did it, I put in some octane booster. Ran it down to about a quarter tank and refilled with premium. I never really noticed any issues, but now I wonder if there is a residual amount of regular gas that caused the problem a couple of weeks ago.
I need to be better about driving it regularly and keeping fresh gas in it. I'm going to keep your list of ideas in case it starts acting up again.
thanks again
I have not driven it for a couple of weeks, so I just took the car out for ride, to get a feel for the way it's running. I did my normal twisty route, and then got it up to highway speed on the way home, about 20 miles total, and it ran fine. Did not seem to miss a lick.
One thing I did not mention: my wife put some regular gas in the car, a tank before the current one. After she did it, I put in some octane booster. Ran it down to about a quarter tank and refilled with premium. I never really noticed any issues, but now I wonder if there is a residual amount of regular gas that caused the problem a couple of weeks ago.
I need to be better about driving it regularly and keeping fresh gas in it. I'm going to keep your list of ideas in case it starts acting up again.
thanks again
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