rough idle after warm

[bladesC4]

My 85 idles rough after it's warm. It also starts slightly harder. Could this be the mass air flow sensor and is it hard to change ?

also the side of my dash with the oil pressure readings is dimmer than the rest. it is normal at night but day time driving is dimmer. what is the key to fixing this. any help is appreciated. This is my first post here. Looking forward to many others

BC4

 

[vader86]

If you can see the numbers on the Oil pressure readings, its just the bulbs inside. Remove the black plastic bezel and youll see 4 silver tabs, twist and remove. The bulbs are inside, they are Sylvania 882s, replace ALL 4 of them, and do not touch them with your fingers, skin oils will cause the bulb to get too hot and blow.

It is possible that the MAF is causing it, try unplugging the sensor when it gets to missing again. If the idle improves, thats the problem. It may or may not throw a Service Engine light.

 

[gray85]

I have a simular problem with my 85. My problem involves the 9 injector (cold start injector) which turns off at about 160 degrees. At that point the car runs lean, causing the idle to cycle up and down till finally reaching a low value. I have tried several things and my thought is that the computer is hosed, I will be replacing it next.

 

[bladesC4]

thanks for the input. I can't wait to try the fixes. I am new to the C4's and find them somewhat intimidating. (afraid that if I pull the wrong wire it will mess everything up and never start again) :eek
I'll let you know how it works.

 

[Daryllawman]

Welcome to the Corvette Action Center bladesC4....

 

[RedRagTop]

bladesc4; Welcome to
How warm are we talking here? When hot mine will be a bit harder to start and maybe rumble a touch at idle. I would check the common tune-up items before playing with the MAF, it is delicate and expensive. If you didn't get a Service Engine Soon light it may just need plugs or wires or a new air filter or something.

 

[bladesC4]

Thanks for the welcome ! I have waited until my 41st birthday to get my Vette. I had an 80 I sold when my son was born 17 years ago. This 85 was the first Vette I gave my now wife a ride in 5 years ago. He now sold it to me and I love it............
Here is what I know......The plugs and wires have been replaced. The "service engine soon" light came on on rare occassion but it would reset.
Am I being cautioned about disconnecting it to check it as suggested ? :confused It is not very hot just a typical 30 mile drive in warm weather is when I first noticed it. It wasn't over heated. my temp read 210 at the time. I believe that's normal correct ?????? let me know and thanks again. Glad to be back in the seat.
J

 

[94conv.]

Could you have an intermitent problem with one of the MAF relays and have these symptoms, the ses light coming on once in awhile is why I'm asking, I had an 89' and the light would come on once in awhile and it was the relays, That particular car never idled what I would call smooth, I always suspected a leaky injecter

 

[RedRagTop]

Assuming you have the same set-up as mine the two MAF relays located behind the battery are easy to change and cheap at about $15 each. Periodic maintenance suggests changing these relays during longer term upkeep.

 

[bladesC4]

Ah yes ! the pieces of the puzzle begin to form a picture. I will check the relays as well. I am somewhat nervous about messing with a $300 MAF. This is where what you don't know you don't know can mess you up.