slight miss
Thread Starter
Advanced
Joined: Feb 2007
Posts: 94
Likes: 0
From: Beloit Wisconsin
slight miss
I have a 95 vette with 80k car is starting to have a slight miss car excellerates fine has a miss with cruise on around 70-75 mph and at a stop light really misses when car is in reverse just wondering if my opti is going bad or could it be plugs and wires I have no cel or codes as of yet.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
I would try to isolate the mis to one cylinder.
I would look at the plugs and wires in the dark and check for any sparking especially the coil wire. Rev the engine too.
Make sure the wires are securely snapped on to the plugs.
I would do this before I started changing wires and plugs so you at least knew what the problem was.
I would look at the plugs and wires in the dark and check for any sparking especially the coil wire. Rev the engine too.
Make sure the wires are securely snapped on to the plugs.
I would do this before I started changing wires and plugs so you at least knew what the problem was.
Last edited by pcolt94; Mar 23, 2014 at 04:29 PM.
Melting Slicks
Joined: Dec 2008
Posts: 2,772
Likes: 64
From: Mystic CT
Knowing what cylinder does not tell you what is wrong. All the tune up parts are 20 years old and all suspect. If only steady state cruise with cruise control on I would suspect injectors O2 sensor or cruise control diaphragm with a vacuum leak.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
You are right, it will not tell you what's wrong. But this a beginning step in the troubleshooting, not an end result. Before most people install parts, they at least want to know what the root cause of the problem is. Yes the wires and plugs are old and should probably be changed anyway.
If you want to install plugs and wires you can hope for the best the it will correct the problem. And if it does not, then you can move on the higher level troubleshooting procedures. I would think the shop has their own repair procedures.
A bad O2 does not do that. Poor swing voltage might cause poor gas mileage. If it does not produce the swing voltage that the PCM is looking for, it would not go into closed loop and would default to open loop A/F fuel ratio. A Tech 1 or 2 (or scanner) will tell you if it is in closed loop and the swing of the O2 sensors.
A leaking cruise servo can be easily checked by just connecting a hand vacuum pump to the thin hose of the servo and pumping it up to 15 or 20 inches. If it holds vacuum, then that is not a problem. That will basically checks the vacuum solenoid plunger and seat seal. Diaphragms don’t go bad as much as you would think. It's usually the seat seals of the solenoids.
If you want to install plugs and wires you can hope for the best the it will correct the problem. And if it does not, then you can move on the higher level troubleshooting procedures. I would think the shop has their own repair procedures.
All the tune up parts are 20 years old and all suspect. If only steady state cruise with cruise control on I would suspect injectors O2 sensor or cruise control diaphragm with a vacuum leak.
A leaking cruise servo can be easily checked by just connecting a hand vacuum pump to the thin hose of the servo and pumping it up to 15 or 20 inches. If it holds vacuum, then that is not a problem. That will basically checks the vacuum solenoid plunger and seat seal. Diaphragms don’t go bad as much as you would think. It's usually the seat seals of the solenoids.
