I have an 87 Iroc 5.7L automatic 89k miles where a misfire on cylinder 6 was diagnosed. It was running rough and would start bucking and shut down on long drives every 150 so miles. I'd turn it off and 10 minutes later would run again but rough and a decent engine vibration. This kinda came out of nowhere. Now on a short drive the engine vibration is bad as well

A shop I took it to said it was a misfire and could be an injector. They checked plugs, wires but wasn't the problem. They couldn't do any engine work because they're backed up but we're trying to sell it and don't know if it's worth spending a lot on engine, or just selling it as is. We might not get the money back out of it if its major. Other than the engine issue its in great shape.

Anyone know what the issue might be and costs for any of the possible issues? Thanks.

 

Moving an injector to see if the miss follows it should be a quick test. Can you pull codes? I may be worth fixing because any decent purchaser will assume it is major engine damage since you are not fixing it. That is what I would advise to someone looking at the car. Its going to narrow the field of people buying and all you are going to attract is bargain hunter and flippers. I would be temped to pull number 6 plug and take a look at it.

I would not mind finding a car like that myself, want to trade for a 93 Z28 no rust LT1 6 speed car with some electrical issues, needs paint and interior work?

 

Thanks for the advice. Think we'll get it worked on and hope it won't be too much, but what you said makes sense. Just drove it back from the shop it was sitting at. I have to keep it in 2nd going through town which it drives fine even though SES light is on. In Drive it starts bucking. Overdrive, forget it. I'd trade it but really need the money from a sale right now.

 

Was the check engine lite flashing? Sure sounds like more then one cylinder.

I am not really in a place to buy a car but I would love to have a 3rd gen again and I was joking about the trade, Last thing you need is a car with an electrical issues. You should post here your asking price. If the motor is damaged maybe we can work something out. How far a drive is it to you from Philly?

 

Compression check/
Add a can of injector cleaner through fuel tank?

 

Engine light wasn't flashing. 2nd gear it actually drove fine 25 mph in town but higher gear it bucks/vibrates. Its not easy finding a shop in western northern Virginia that will work on it but I'm taking it to another shop Tuesday that can hopefully diagnose and fix. They will be doing a compression test.

 

Good luck. The check engine light will flash once a miss is so bad the computer is not seeing any fire to the cylinder. This should be pretty easy to diagnose with the right tools. The right tools being a scanner that can count miss fires and oscilloscope. It sure sounds to me like weak spark breaking up under load but it could be a lean condition the O2s are not picking up. But those are just guesses based on frequency of failures. It could still be hardware like a worn cam or stretched timing chain or even valve sealing.

BTW Nice looking car. I cannot imagine a scenario where it would not be worth fixing this car. I am sure selling it with a miss fire will hurt the value of the car more than the cost of a repair. .

 

That was a thought that crossed my mind.

Agree 100%

 

Thank you. I'll tell the shop to check for that.

 

Shop said no compression on cylinder 6. Not a plug issue. Didn't diagnose what it specifically is. It drove home fine 25-40 mph but anything approaching highway speeds and it will vibrate.

Any engine shop that I'd actually take it to is backed up until January so I'll be selling as is.