check engine light blinking(help asap)

hello people, first thank's for trying to help me, ok this is the problem, the check engine light start blinking when i drive more of 3 miles.
I took to a shop and they detected misfire #6 they did a tune up, after that the light still same, they send me to the dealer and this guys made a few things: replaced injector #6, replaced three wires crankshaft position sensor and when they made a road test the ear knoking noise in the motor when the idle go to 3000 rpm that cause a retarding in the timing 30 degree, so they told me that is possible that i going to need a new motor.??? :screwy: the jimmy runs fine, any problem, just when the idle go to 3000 rpm, but the check engine light was blinking for a year and the problem of the 3000 rpm start a few month ago, will be going bad? but now is time for the emission and will not pass :banghead: . ANY HELP WILL BE GREAT!!! THANK'S A LOT :rolleyes: :
lucho.-

What year is your Jimmy?What is the engine code? How many miles do you have on it?How is your oil?If your ses light is blinking then your car has an issue and you should not drive it..A blinking ses light means that the problem is damaging other components..

I have a simiar problem where my check engine light blinks for about 30 seconds when ever I take the truck on the highway and the speed is around 70 mph and going up hill. There is one particular place on a parkway where you have to accelerate while going up an incline and almost every time, my check engine light comes on for a short time, then goes off by itself...repeating this cycle for 2 or 3 times, then stays off.
I have taken my mechanic for a ride through this spot with the code scanner attached to the computer (because the engine never stores a code after this happens) but nothing shows up on the scanner even while the engine light is flashing. The mechanic is at a loss. This has been going on now for over a year....so far with no apparent engine damage. :banghead:
If anyone knows whats going on, I'd sure like to know also!
Mine's a 1997 Jimmy 4dr 4X4 Auto

hello people, first thank's for trying to help me, ok this is the problem, the check engine light start blinking when i drive more of 3 miles.
I took to a shop and they detected misfire #6 they did a tune up, after that the light still same, they send me to the dealer and this guys made a few things: replaced injector #6, replaced three wires crankshaft position sensor and when they made a road test the ear knoking noise in the motor when the idle go to 3000 rpm that cause a retarding in the timing 30 degree, so they told me that is possible that i going to need a new motor.??? :screwy: the jimmy runs fine, any problem, just when the idle go to 3000 rpm, but the check engine light was blinking for a year and the problem of the 3000 rpm start a few month ago, will be going bad? but now is time for the emission and will not pass :banghead: . ANY HELP WILL BE GREAT!!! THANK'S A LOT :rolleyes: :
lucho.-

Go get the codes scanned.

I have no idea why you drove a year with a truck running with problems like that.