feels like its stuttering or missing while driving it

[seabass1858]

I hate to be redundant with my posts but I just drove it up the street and back to put gas in it and it seems like it is underpowered and is stuttering and going up a hill, I have to downshift early. I let this sit since June before I deployed but now that I am back, I kind of need my car to work right so I can drive it to Pennsylvania. Where would you start.

[berettaboi]

coil packs or ICM likely. what engine? always state what engine you are dealing with right off the bat...

[seabass1858]

3.1 1991 gt. the ICM was replaced prior to deployment because it was having issues when warmed up but ran fine cold. it doesn't matter what temperature it is now the way its acting.

[88*Beretta]

put gas in it and it seems like it is underpowered and is stuttering and going up a hill

Does local station sell E10 fuel? If so, its possible you got a different blend, like E20.

[Money pit Beretta]

Water in the gas?

[seabass1858]

I wouldn't see how when it was stored in my climate controlled garage along with my 1960 willys jeep which fires up perfectly fine, It is just too cold to drive that to P.A

[GTU89]

Try the coils, I had practically the same problem and it turned out to be the ICM, so I would try the coils since you already changed the ICM. You could get both the ICM and the coils tested at AutoZone to give you an idea.

[seabass1858]

I pulled one of the spark plugs and its pitch black so i will start there

[Koots]

I know most people think I'm friggin crazy, but if your plugs are that black, I'd try finding a good manifold vacuum source (one that will feed all the cylinder as equally as possible), have someone keep the RPM's up and modulate the throttle, while you suck some cold clean water through the engine.

It's gonna spit and sputter but try not to let it suck in too much water or stall out. With the engines RPM's up, it should suck the water right into the engine and basically steam clean your combustion chambers.

It sounds ridiculous, but it works and I've done it with everything. My old 4.3L GMC, my 6.0L 2500hd, my 1.6L Honda and a few other vehicles as well. I find doing this, then doing a seafoam cleaning later in the exact same way, will usually get a rough running, high mileage vehicle running much better.

It's not always the solution, but it's basically free and , with common sense, very safe for the motor and all sensors.

[88*Beretta]

I pulled one of the spark plugs and its pitch black so i will start there

GM injectors can get pintle varnished when stored, and sometimes, they don't work at all after storage.

I'd try some Chevoron Techron.

[seabass1858]

I hope its not the injectors because I replaced all 6 of them a year ago and they only have 10k miles. I find it funny that my 52 year old jeep fires up fine. I use to take the beretta to the parts store for the willys and now im taking the willys to the parts store for the beretta.

[88*Beretta]

have someone keep the RPM's up and modulate the throttle, while you suck some cold clean water through the engine.

I think they use SeaFoam these days...don't know, never done this type of thing; just pull the heads off, and look around, or get one of those micro-camera scopes.

[88*Beretta]

I hope its not the injectors.

GM had some bad designs years ago...YMMV.

But, I've read somewhere, one needs to run some chemical/cleaner in them before they set for long period of time.

Fuel Varnish, just Google it, it takes out injectors and carburetors.

Myself, I put some 15,000 to 20,000 miles a year on my main driver; its tank has no fuel varnish...but for those who fill their tank once a month, or let vehicle sit, sit, and sit, then here comes the fuel varnish.

When using E10 fuel, you get separation of fuel when enough moisture exist in tank, and if you let it sit with E10 fuel in tank; then when you start it up, you burn pure ethanol.

[seabass1858]

Ill get it running right off of Georgias finest moonshine lol

[3X00-Modified]

Judging by your other thread I want to say the coolant temp sensor that controls the Fan and the ECU is bad... I just don't know which one you replaced already. There should be two of them, one feeds the dash signal only.