I have an 84 Z28 305 5.0 HO, auto, stock, 82,000mi. The other day while driving at a local recreation park area where speed limit is kept at 25, I noticed my check engine light came on for about a minute or two and went off. This was while I had it at steady throttle for a little while at low rpms. Could that somehow effect a sensor or something? I've only had the car for a few weeks and it never came on before. This is the first time that I drove it at a constant low rpm level like for a long period of time though. The engine didnt sputter or anything and ran fine the rest of the way home. I checked all the fluid levels when I got home and they were fine. Any ideas? Thanks.

-ps, this is my first post here

 

You need to check to see if you have any codes that pop up. It is real easy with a paper clip, and cheap to. The check engine light will flash a code and it will tell you what the problem is.

 

Hey, thanks for such a quick answer. Could you tell me how this is done? Where would the code be displayed? And will this work when the check engine light is off? Cause it was only on for a minute or two. Thanks again.

Oh and I also read somewhere on a search in this message board, that Autozone checks this for free. Is that true?

 

Autozone might check it for free but you can DIY. See article here.

 

Alright. I do this all day...haha.... If its before 96 it probably doesnt have OBII so you need to look for the connector under the dash and put the paper clip (or a GM key you can get for free at AutoZone) in the top right last 2 prongs so it completes the circuit. Then on the dash your check engine light will flash followed by spaces. The start of the test is "12" so it will flash once and then a space and then flash 2 more times followed by a space. It will repeat this 3 times and it will repeat each code 3 times so you have time to write them down. The end of the test will flash "12" again. With your codes you can look them up on the internet or in your haynes manual or just call AutoZone and give them the codes over the phone.

If your vehicle does have an OBII sensor your gonna have to take it to AutoZone for a free test. Most car dealers charge $75 and up for the test. Theyll plug it in and it will pull any codes that are there. Probably the 2 most common codes that I pull are O2 sensors and EGR valve. If it is the EGR valve just get some carb spray to clean it up. If that doesnt help you might need a new one.

Hope this helps.

 

Haha....why did I type all that?

 

hey white kid, i gotta question for you,
my moms car started up the other day and then randomly stalled a few seconds after, it never did it again since then. but i flashed the codes by grounding one of the pins and i got codes for knock sensor, o2 sensor, and something that seemed like an IAC sensor.

anyway it might not have anything to do with those codes at all. the check engine light did not come on and those codes might have been old. why does the o2 sensor always seem to be a common problem with the cars you've seen, and does it mean that it needs to be replaced or could it just be having a bad day

thanks

 

I don't think an 02 Sensor can have a bad day.
If I were you, I would clear the codes (disconnect the battery for a few minutes, or if you don't want to loose your radio presets and such pull the fuse for the ecm for a few minutes). You can scan it just to be sure you cleared them. Give it a couple days, and scan it again. Work from there.
02 sensors go bad usually between 50,000 and 100,000 miles. For that reason most people replace them every 50k or so whether or not its throwing a code.
02 sensor is $20, so your not going to go broke on that one, I cannot imagine the knock sensor being too expensive.

As for scanning the codes just do the paper clip thing. Just don't start your car with the paper clip in there.

 

Sounds like he got it The only thing is what kind of car your mom has will determine the price. The cheapest O2 sensor I've seen was $40 for an O.E type, and I replaced 2 O2 sensors on my grandfather's Camry and they each costed $160 for the O.E. type so I just went for the universals for $70 and spliced the wires together myself. Very simple job.

 

thankyou for your response


yea i know the OEM stuff is alot of money, and thats what my dad wants me to put in also. i was also thinking that it could have something to do with the fuel filter because i dont think its ever been changed. i told my dad i could take care of the fuel filter myself becasue hes going to get an inspection for it and wanted to get everything done at once so i told him just to flush the tranny and coolant with the machines they have and i would do the tune up stuff for him.
i had a couple of quick q's im gonna put in a new thread about the filter.
also my moms car is a 94 mitsubishi Diamante sorry not a 3rd (if anyone was wondering) but thankyou for answering anyway