Hey
Ever since I bought my 91 Camaro RS 305 TBI automatic...the service engine soon light comes on while I'm on the highway going over 65 mph. it never goes on unless I'm going atleast 65. I replaced the o2 sensor and EGR valve....and for some time after I did each of those....it didn't come on. I'd say it comes on 40% of the time now when I'm going over 65. Once it comes on.....it doesn't turn off no matter how fast I go, unless I turn the car off. Does anyone have any ideas? because I don't really have the time or the money to take it to the shop to get the codes read. Thanks a lot

 

i actually had a similar problem on my '87. . . my engine light too would come on during highway driving, and it also seemed like it would only come on when i'm like really crusin'

so i ran a code scan i got the MAP sensor code... so i got that replaced and since i haven't had any problems w/ the light soming on...

so i don't know, i guess it could be your MAP sensor.

 

Thanks......what exactly is an MAP? lol sorry I'm a newbie. Also, how much is it to get replaced? Thanks

 

It would be easier to get the ECM scanned to find out what code is turning on the SES light. What was said about one car does not mean thats your problem.

 

Find out what code is causing the light to come on first. Then, you can determine what to replace. My '92 RS did the same thing and it was code 32 which was too much hot air getting into the intake manifold after the engine was warm. To fix that problem, I took out the old air cleaner setup and put on a 14 X 3" Open Element w/ a K&N filter. Ever since then I haven't had a problem and that was probably 6 months ago.

 

MAP = Manifold absolute Pressure

 

How to pull your own codes:

Turn off the car. Take a paperclip and insert one end into the upper right hole of your diagnostic connector, and the other end into the hole next to it. Turn the ignition on but DO NOT start the car. The SES light will start to flash. It'll flash once, then pause, then flash twice. This is a code 12 and means the diagnostic computer is working normally. It'll flash code 12 3 times then proceed to any other codes stored in the computer, flashing them 3 times each. When it's done it'll flash code 12 again. Turn off the ignition and take out the paperclip when it's done.

Get your codes and bring them to us and then we can help.

 

Thank you for all the info

Well I took it to Murray's Auto and had them hook up the electric code detector. Nothing came up......They said the engine light has to be on for it to show up....sh*t!!!!!!!!!!!

 

Still should of had the last code stored, unless you disconnected the battery.

 

Don't take it back there. Follow what TheGreatJ said. Any code ever set is stored until the power is removed from the ECM for roughly 1 minute.

BTW - your connector is under the driver's side of the dash, near the center console