Motor revving at stoplight...

[Old77]

Ok, this is a question on a small issue in experiencing with my caprice on an intermittent basis. It is a 305 tbi if that makes a difference. The last few days when at a stop light the engine will rev on me while my foot is on the brake. Then it'll go back down to normal idle. It won't happen every time but has happened a couple of times. If I'm at the light long enough it will happen a second time. When this happens the Service Engine Light will come on. I have not had a chance to try and see if I can get a code and as soon as the issue clears the light goes back off.

Any ideas?

 

[oneluckypops]

would be nice to know what the code is, But possably EGR. or IAC

 

[Old77]

Yeah, I'll have to get my code reader and have it with me when it happens again. I've found those old school readers hard to use at times, though. I'll have to see what I can do.

 

[bucket]

You don't need a code reader and you don't need to wait until it does it again. Jumper the two pins on the diagnostic connector and just count the flashes. It will flash a sequence for "12" three times and then flash each code three times, then flash "12" when it's done.

 

[Old77]

This is probably a stupid question but how do I jumper the diagnostic connector?

 

[Jims86]

You don't need a code reader and you don't need to wait until it does it again. Jumper the two pins on the diagnostic connector and just count the flashes. It will flash a sequence for "12" three times and then flash each code three times, then flash "12" when it's done.

Pins A and B
You may get a VSS code, from what you 'splained.

 

[crazy4offroad]

A paperclip works great.

 

[Jims86]

Yes, paper clip.

You must be registered for see images attach

 

[Old77]

Ok, so you put a paper clip in terminals A and B. then what will flash to let me know why code it's throwing?

 

[Jims86]

After you jump A and B, turn the key on. Watch for check engine light. First code will be 12(flash......flash,flash) that will happen 3 times, any codes after that will be the issues, unless it just keeps flashing 12.

 

[RetroC10Sport]

The check engine light. It will flash once, then twice...It will do that three times. Then let it keep going and count the flashes.

 

[Old77]

Ok so the 12 flash will happen 3 successive times then it'll flash after that and the amount of times it flashes will be the code of the issue. When I turn the key to on does the engine need to be running or just the key in the on position?

 

[Jims86]

Ok so the 12 flash will happen 3 successive times then it'll flash after that and the amount of times it flashes will be the code of the issue. When I turn the key to on does the engine need to be running or just the key in the on position?

Engine off, key on...do not start!

 

[Old77]

Cool! Thanks guys! I'll give this a try in the morning and report back is there a website that'll tell me what the code means after I'm done counting flashes?

 

[crazy4offroad]

Morning??? Figured you would have done it already!