1995 Chevy Lumina 1995 Chevy Lumina APV

KMG

MEMBER
1995 CHEVROLET LUMINA

1995 Chevy Lumina

This vehicle will start perfectly, idles quiet and smooth. The problem is when you put it into gear and you start driving. You will drive for about 5 minutes and then it starts shaking, and acting as if it wants to stall out while driving. But it never has. Then when you stop at a light or anything like that it goes back to idling perfect. Our mechanic has replaced the fuel filters and the EGR Valve, and since then now the Check Engine Soon light has came on and when I take it to them they say that there are no codes being read on it. I have been told so many things by so many different people. My question to you is what do you think it is. I also have put the highest octane fuel in the vehicle per the request of our mechanic. I am on my way to get a crankshaft sensor position for the vehicle, because from what I have read on your fourms that could be a possibility, and its a relatively cheap fix for us. We spent $400 on the vehicle and now are up to over $1000 in mechanic bills. Kinda starting to become discouraged.
Please HELP!

1 Reply

MMPRINCE4000

MECHANIC
8,549 POSTS

You will have to begin a diagnosis process before throwing parts at it again.

Check fuel pressure with a mechanical gauge.

Check spark with spark testing tool, look for blue snapping spark.

Check backpressure on convertor, CAT may be clogged or partially clogged.

High octane fuel on a car designed to run on 87 octane is an indication of masking a problem.

Since this is a 95, it is an OBDI ECM, and you would need an OBDI scanner, but you can retrieve codes on OBDI cars by shorting terminals A and B of the diagnostic link. Check engine light will flash codes.

First deciede if you want to work on car yourself, you will need some tools and some speciality tools.
If you want car worked on by mechanic, shop around, look for shops that have been in business for many years, have ASE certified mechanics, BBB certified and clean shop (if you walk into shop and have to dodge transmissions lying on floor, then find another one). Stay away from chain repair shops.