Hi Guys, new member here.

I have an 88 IROC 5.7 TPI all stock except a chip. Sometimes on startup the check engine light comes on and the engine idles rough at about 500 RPM as opposed to 600 RPM normal. When this happens I can shut it off and wait a few seconds and restart and the problem goes away. The check engine light does not come on during driving, only on startup and not very often. I do notice a slight surging at cruise speed ( hardly noticable ). Sometimes I have to restart several times for it to start clean. I have not pulled the codes yet.

Any ideas ?

Also, what are the stock gear ratios for this car? I checked the RPM at 60 MPH 3rd gear (auto) and it is about 2300 with 25.5 inch diameter tires I calculate 2.90 gear ratio. Is that about right?

 

Well what i would is first off pull the codes. Put the ignition on but do not start the engine. What that invloves is a jumper wire, preferbly a paper clip. Locate the ALDL under your steering wheel to the right. Connect between terminals A and B(the 2 terminals farthest right and on top section of connector. Well it will flash like morse code. For Example blink-pause-blink,blink = code 12. Which means your diagnostic system is functioning. Get the codes and write them down. If you don't know what they mean post them, and you shall recieve answers. Hope this helps a little.

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88' IROC-Z, 350 TPI, 700-R4