cghel54

I put my 94 in a Chevy dealer for an oil change. When it was done and I was to leave, I put it in gear and got a rough surging - misfiring, very rough idle. Service Manager says all they did was oil change - no responsibility for rough idle (car was perfect when I dropped it off). They couldn't find anything obvious - nothing loose etc. Kept it overnight and said probably a distributor. They said Corvettes had problems with distributors in that year letting moisture in and corroding the electronics. $1500.00 to replace. My feeling is they are responsible to return my car in the shape they received it. Any thoughts? Any idea of moisture issues for that year? Thanks, Calvin

cghel54

I forgot details - bought in June 2012 with 21,000 miles - now has 22,000.

Drew

Sorry about your problem. I would stay away from Dealerships, especially with older cars. The Tech's are only up to date with the newer cars and most don't know and don't care about the older stuff, especially C4 LT1's......I personally would not let a Dealership put air in my tires..They are trying to sell you a new Optispark Distributor, which were on '92-96 Corvettes. $1500 for just a new Opti installed is pretty expensive IMO. Usually when you replace the Opti you also want to replace the Water pump at the same time. Yes, moisture and or a leaking water pump can destroy an Optispark....Good Luck dealing with the Dealership...

dr_cranii

Or just simple engine wash can cause this behavior if there is a crack in it or bad seal or screw is not tight.. Etc.

theadmiral94

Whereas sometimes the distributor will give symptoms similiar to what you have experienced, there can also be many other components which could cause the same issue.

The mileage on your car suggests that distributor and cap (absent of leaks from the water pump or engine washing) should be fine.

Did they extract a 'code' which specified the distributor is the problem?

They should have a 'tech 1' or 'tech 2' diagnostic service computer which can eliminate a 'probably' and make it a 'confirmed'.

There are specific tests contained within the FSM or numerous info here on the forum which can confirm or dilute the distributor being the problem.

The OPTI is just a normal distributor (distributes the spark from the coil to the plugs) and a crank/cam position sensor -- all combined into one device. The sensor part sends two signals to the ECM, and analysis of those two signals can confirm or dilute the OPTI as being the problem.

Examples of other possible components to cause similiar problems are: bad ground, ECM, ICM, MAF, fuel injector(s), fuel pressure regulator, fuel, plug/coil wires, etc.

Presume you have car back, so suggest extracting the 'codes' yourself and acquiring (if you don't have) FSM and running the diagnostic trees yourself.

Also, check all the connectors in/near the oil fill area, in case they 'accidently' damaged one of the connectors so as to sell you an OPTI.

As a hint, on my 94 with 100k miles, still have original ECM/MAF/fuel injectors, and fuel pressure regulator, but do have a new OPTI installed around 75k -- and just recently had the ICM (Ignition (coil) control module) die and had to replace it -- symptom was no-start -- but did eliminate hessitation -- so worthy to at least check to see if your ICM is tight (14 inch lbs) and its plug and other coil connectors are properly connected.