Dirty_Bird_LT1

Okay guys, my LT1 feels a bit weak and has a slight miss when it gets to about 4,000-4,500 rpm. It's also getting HORRIBLE gas mileage. I am currently in the process of replacing the plugs and wires. I've replaced the fuel filter and swapped all fluids out. There is no code being thrown. I'm just hoping it's not the opti at 73k miles. lol

Dirty_Bird_LT1

Also, how do you get plug #8 out. I've done every plug and wire except that one. It's a biatch. I will try to finish the car up in the morning.

ReggieWarrenJr

iTrader: (11)

if the plugs and wires dont do anything and you have fuel pressure, its most likely the opti.

Dirty_Bird_LT1

That's what I figure, but I'm in denial about it. haha! I don't know what GM was thinking when they designed that ignition system. lol!

Cam95Maro

iTrader: (1)

Mine was a coil. I replace coil and icm while i was there and it cleared up

Dirty_Bird_LT1

It's definitely the Optispark. I've replaced everything tune-up related along with a coil. DAMMMIT! LOL!

warriorcustoms

iTrader: (10)

A miss with shitty milage IS most likely the coolant sensor in the water pump!!!

Dirty_Bird_LT1

Would the coolant sensor throw a code?

01fxst

I hadn't thought about that myself. But since the sensor in the pump feeds the PCM it could be sending bad data. Only way to know for sure other than swaping the sensor would be to connect a laptop to the PCM and see what it is reading.

Otherwise I was going to say Opti. I would have thought a miss with shitty milage would be ignition.

DisasterFormula

iTrader: (1)

Bad ECT is supposed to throw a code. But then again, bad O2s don't always throw codes.

96capricemgr

iTrader: (1)

The opti is not a bad piece, stupid people who think a distributor cap and rotor should be permanent life of the vehicle pieces are the problem.
Nobody bitches about a cap and rotor change on an HEI smallblock hell most who drive them will just change them as part of a tuneup over other year or so way short of 73K miles.

Far as the coolant temp sensor a bad one can cause bad mileage and such and if it were bad enough to set a code the pcm would then ignore it and the car would run better. The car will generally run OK once a sensor actually sets a code, it is when a sensor is sending incorrect info that the pcm is trying to use that it runs bad.

warriorcustoms

iTrader: (10)

Corrosion or build up from Lack of maint.... wont ever set a code LoL I will bet you a dollar its that & if it was my motor I would do A Complete Tune Up IF I remember right @ 60k its time for that LoL I Have worked on many cars that never threw codes & had parts that were **** LoL

Bigtoyz

iTrader: (2)

if it runs fine up to that point 4k rpm my money is on the opti. I had same problem it ran fine to 3600 and spit, sputtered, and bucked like a mule...lol