After having my cars latest problems taken care of, it still keeps dying on me. .it has been doing this nonsense for about two weeks now. . and when it dies, it will not start back up. . i have to sit and wait about ten-twenty minutes for it to start.. all it does is sit and crank. . i recently got the opti replaced, and after that a hose blew out on the water pump. . got that taken care of too. . but sometimes when i hit the gas to hard, or when im just rollin around it just dies. . i have made sure the fuel pump is clean too. . it's got great fuel pressure. . its about 43 or so. . i dunno what the problem is. . anyone got a solution?

 

What year is your car? Is there an SES light present and if so, have you had it scanned?

 

Its a 97 Z28. and yes. . the SES pops on and off every once in awhile. . we have scanned it and the only code present is the random/multiple missfire. . nothing else shows up. . thats what i don't understand about this car. . its got 65000 miles. .but thats all we could pull up

 

At a guess - Ignition Control Module. Mounted on a heat sink next to the coil on the drivers side head.

 

What replacement Opti did you go with and when the hose came off did the Opti get wet?

 

it's just and ac delco opti. .and no. . it did not get wet. but i still don't know why it keeps dying. .when i drove it home last night, i was seeing the rpm gauge go crazy then just drop to 0. it was doing it while the car was idleing too. . i havve never seen this problem before. could it be the MAF sensor?

 

You can have the icm tested at AZ, might as well take the icm and the coil in together as a unit and have them both tested. Make sure they run the icm test 5-6 times, to allow it to heat up and see if it still passes. Good luck with it.

 

Better yet, carry a propane torch with you to "gently" heat the back side of the mounting bracket and heat sink. These things are mounted to the head so they get good and hot. Over time the electronics (Mosfet switch circuit) degrade from heat and heat cycling. When they start to die, they're happy cold and crap out when hot.

Not sure of the tach acting funny though. Somebody correct me here, but doesn't the tach get it's readings from the opti?

 

I had the same symptoms and it was the ICM for me.

 

I work on these all the time....sounds like an icm to me. you could have some water in the ignition system. That will make it miss but not just die. go with the icm and see if it still does it. Does it have fuel pressure when it is dead? Check that too.

 

OK. . i am gettin my car over to my buddy shop today to hook it back up to the computer and see what kind of code shows up this time. . i will have him run the icm test. .and yes. .it has great fuel pressure when dead. still hits about 41-47 psi. so ok. . thanks alot for the info . . i will re-post and let everyone that helped know the results.

 

i would say that too off the top of my head

 

AC Delco is the best OEM choice.

I remember a year or two ago I had gauges jumping around like crazy...ended up actually being the negative battery cable loose on the battery. Created lots of very odd symptoms. It's a long shot, but it's so easy to check, might as well huh?

I once had a brand new "generic" MAF sensor that would be fine until it got warm...then it would just peg out and tell the ecu its seeing 400+ gps of air. It never tripped an SES light. The only reason I caught it, was I happened to have a scanmaster, and after my car started missing and dying I scrolled through the parameters and saw the MAF readings were out of this world. I simply swapped in an AC Delco MAF and it has been trouble free ever since.

Good luck,
Andrew

 

i will second that! OEM opti is the only way to go!