Service Engine Light - 1997 Chevy Express 4.3 Ltr

Hi Everyone,
I would be surprised if I can correct this problem soon but here goes. Any help would be appriciated. I have a 97 Chevy Express with a 4.3 litre engine. Its was running extremely well until I got an oil change. The garage didn't tighten up the drain plug, so I drove it on the highway and the oil drained out and seized the engine. They agreed that it was their fault and they installed a so called crate motor. (not from the dealer) It seems to run ok but the "service engine" light intermitently flashs. There are no codes present. I took it to 3 different garages and nobody has the solution. The vehicle can go days without the light flashing and days with it flashing. It's not like the light stays on for a while and then off...it flashes on and off like a dashboard signal lamp. Thanks in advance
Steve

Flashing light is a engine cylinder miss or missfire.

A good repair shop should be able to find it.
First thing I would check is the camshaft reatard setting.

To find a good repair shop.
Check around Ask around
Word of mouth.
Family friends coworkers neighbors business people and delivery people.
Mailmen and parcel delivery people get around and notice a lot of stuff.
Even a good parts house knows what shops are good and not good.
Chamber of commerce and better business bureau and city hall.
If you find a good referral to a repair shop go look them over and talk to them.
Look for a clean looking busy place with nice people running it.
Ask a few questions and ask about their qualifications and training.
Not all places have trained tech/mechanics.
If they do not find a place that does.
Even all dealers do not have all trained techs/mechanics.

I will do exactly that. Thanks so much. I will post the results.
Steve

After being at the Chevrolet dealership for almost a month (mainly because I didn't need the van as I told them) my problem was eventually solved. Apparently there was a TSB on the 4.3 Ltr engine primarily on pickup trucks and not the Express van, but the dealer figures that the replacement engine came from a pickup. In order to prevent the misfire to cylinder 2 and 5 they had to shim the crank sensor. Problem is now solved. Thanks to all.

You are welcome and.
Thanks for posting back how it went.
Sounds like you dealership is on the ball.
Good old TSB's sometimes do help.
Not all would have found that problem.
Glad you got it fixed and good luck with it.
MT