Misfires and more

**kappa67** · 08-03-2024

Hi all
Had yesterday I had some misfires on my car (2000 Pontiac Grand Prix GTP)
Sometimes he shot off completely.
Whats that? So I changed the ZZP coils to the stock coils.
After the change all was ok...no more misfires nothing

These ZZP coils are from 2020. Thats 4 years a short period and now broken?
I thought this is much better quality than the MSD coils. With MSD you can have many problems.
But it isn't...its very bad and now i wanna ask:
Has someone of you the same?

Should I order new ones or leave the originals in?

**FordMan77** · 08-04-2024

The OEM ones are known to be the best to use. Stick with those and don't look back. If you want you can paint them to make them look non-stock if you want to dress up the bay.

**kappa67** · 08-04-2024

Yes that I did with them...red coils looks good.
And you have not better electricity and so with the aftermarket ones?
More power on the car?

**jeepers** · 08-04-2024

The aftermarket ones, both MSD and ZZP, only look nice. There are no performance gains to be had from them.

**kappa67** · 08-04-2024

News on the car....it shot off again and runs very unclean........
So there are more than the coils.
I don't know maybe the plate under the coils? Other things I don't know...
Next step is to change the ICM module under the coils

**BrandonHall10** · 08-04-2024

What are the codes?

**FordMan77** · 08-04-2024

I have had bad coils take out an ICM a few times. Grab an OEM one from the junkyard (along with the coils, because why not have spares?) and throw it in. Don't forget the ICM wire harness is like a 7mm or something strange. Nuts that hold the ground cable and mount the ICM are 15mm deepwell.

As Brandon also asked, are there any codes? CEL on?

**kappa67** · 08-05-2024

I have no codes nothing

**kappa67** · 08-06-2024

Changed the ICM..better but not good.
Shut off again
I don't know what to do...best thing is to sell/give away this piece of crap

**kappa67** · 08-06-2024

Next thing happen.....if i put the gas down long time after the speed in HUD goes up to 150 and more and don't come down.
TCS lamp is burning all the time
Computer shows 00
I don't know what this could be
I think its more broken than I can think

**BrandonHall10** · 08-06-2024

Where do you live?

Corrosion? Pack rats? Squirrels?

I'm curious if there is an issue with the wiring somewhere. Bad grounds will cause a myriad of strange issues.

**kappa67** · 08-07-2024

I live in switzerland....europe
Here we have none of these cars in junkyards or so. And we haven't so much of them only a few in the whole country.
Before the change of the transmission (rebuild to HD) the car runs great without problems.
But these problems couldn't be the thing with the transmission.
I don't think its corrosion the car is everytime in a box.
It will be very difficult to find out what this is......
If I drive normally all works...and I hope it doesn't shut off
If I put the pedal to the metal then the things I said will come, never had this before

**jeepers** · 08-07-2024

I agree, it sounds electrical. Have you ever had lights go out or needed to jump start? A bad ground and maybe a bad alternator; both can wreak havoc. I have had an alternator fail and cause issues that manifest like transmission symptoms. Grab a multimeter and check your alternator to ensure you are getting full charging voltage.

**kappa67** · 08-07-2024

My alternator is a new one with more power......

**BrandonHall10** · 08-07-2024

Originally Posted by kappa67

Before the change of the transmission (rebuild to HD) the car runs great without problems.

This raises suspicion. Often times when a large component is removed and replaced, grounds get forgotten, wires get pinched or pulled and connectors get crushed.

You also say:

If I put the pedal to the metal then the things I said will come

Makes me wonder if you're missing a connection to the MAP sensor. Vacuum or wiring.

**kappa67** · 08-07-2024

Interesting maybe something forgotten on the transmission
The connector on top of the transmission is the only one?
Ordered a new Wiring harness maybe is here the problem.

**tomsteve** · 08-08-2024

Originally Posted by kappa67

Before the change of the transmission (rebuild to HD) the car runs great without problems.
But these problems couldn't be the thing with the transmission.
I don't think its corrosion the car is everytime in a box.

this is reading like a power supply issue .
take a thorough look at all wiring. there's a harnesss that runs up the front of the right side and breaks off to sensors and other necessities.its to the right of the oil fill cap. pull the insulation back and inspect the wires. sometimes the insulation on those wires can wear. clean bat terms and grounds. I believe there are 3 main grounds to check? even if positive cables from battery look good they can be corroded internally.

**kappa67** · 1 Week Ago

Hi FordMan77
Think you're right stock ones ingnition are the best
I buyed some:
https://www.ebay.com/itm/395245468294
Dont know if these are stock....seems so.

**jeepers** · 1 Week Ago

Those are not stock. Stock ones would be either Delphi or ACDelco. You can get both at RockAuto.com. Based on the images at Rock Auto, I suspect Delphi is the stock version for most 3800's.
2001 PONTIAC GRAND PRIX 3.8L V6 Supercharged Ignition Coil | RockAuto