94sleeperZ

Ok, here is my problem.

94 Lt1 Camaro, SLP exhaust, hypertech chip, K&N Intake, 180 degree thermo.

Car runs fine when cold or just started. Runs for 5-10 minutes starts to run sluggish and wants to stumble/hesitate at cruising speeds. After the car runs for 30-40 minutes. It gets worse and barley stays running. GAS Mileage has dropped off horribly. Will burn a half a tank of gas in a 30-40 mile round trip.

I have taken the car to three shops. All say the car runs great.
Here is a list of items that have checked ok or recently installed

Fuel Pressure
Fuel Pressure Regulator
Plugs
Installed a new MAF
Installed new plugs
Installed new Opti
Installed new Coil
Installed new ICM
Catalytic pressue check... was ok

The last shop I took it to said it had two Codes

Code 44 Bank 1 O2 sensor low res pulse and
Code 34 Map sensor

Here is the thing, I unplugged the MAP, car runs the exact same way. When its in closed loop. I am thinking its plug wires????? But I am torn because it could be the O2 sensor too???

Just wanting some help before I change the wires since they are a Pain in the &^%$&

Also this issue has been around awhile.. just keeps getting worse. But I hardly drive the car. But the gas consumption now is so bad I can hardly afford to drive the car. Any help would be great.

matt94z

iTrader: (49)

Sounds like a bad o2 sensor to me. If you had a burnt wire, it would more than likely miss all the time.

matt94z

iTrader: (49)

How does it run at wot? The o2's aren't used in open loop which is on startup and wot

94sleeperZ

Under a hard acceleration the car runs fine (which is why i think the shops are saying it runs good, because they are out running the crap out of it) But at a constant cruise speed it bucks, hesitates and runs like DUMP. When I do get down on it, black smoke pours out the back like a Diesel.

My biggest hang up is when I unplug a major sensor and the car goes into open loop it runs the same??? Likes its a mechanical issue??? Thats why I am torn between plug wires or the O2?? I know enough about OBDI to be dangerous but not enough to pin point a problem. Does the car still run off O2 sensors even in Open loop????

Thanks again

Stroked96Bowtie

iTrader: (22)

Replace that o2 sensor in bank one...don't get a cheapy...Napa only if not from a cheverolet parts house as the first option. I've bought autozone/orielys sensors before, don't bother. There are front and rear o2 sensors, be sure you replace the right one. Those sensors aren't cheap.

Also double check the wiring near where it mounts in the exhaust, just to be sure one isn't bad or got burnt.

Plug wires are easy to check, wait till pitch dark night and start the car. Should be a lightening storm under your hood if the plug wires are bad.

94sleeperZ

Ok, thats what I am going to do. Yeah I dont buy the Autozone junk, napa or Orielly. Wish me luck I will keep everyone posted. Man I hope this is it. I have spent alot of money on this one stupid problem

94sleeperZ

Any other thoughts before I sped 50$ on an O2 sensor???

SS RRR

iTrader: (2)

Unplug the O2 sensor and drive the car. See what happens.

94sleeperZ

It runs the same??? It goes into open loop, check engine light comes on, the fans start running, but overall the car runs the same?
Thats why I am thinking it something mechanical, like the plugs. BUT the problem doesn't start until the car gets warm. I am so confussed

matt94z

iTrader: (49)

O2 sensor

SS RRR

iTrader: (2)

If it's acting up in open loop then it's not the O2 sensor.

94sleeperZ

thats the same thing I am thinking. By why is the problem only act up when the car is warm?? Plugs should be all the time, I have good fuel pressue and the opti is new. So i have good spark, I have good air, and I have good fuel. Could it be timing, and the hypertech chip has screwed up the computer? (side not the car runs the same with the chip on it or not)

Thanks guys for the help

Cody

SS RRR

iTrader: (2)

Check to see if the waterpump is leaking on the opti. I had the same problem where car would stumble only when warm. Come to find out the w/p was leaking only once the coolant was pressurized.

94sleeperZ

Its dry... Something else. The SMOG Pump runs all the time, I mean constantly. I dont know why it would always be on. Also the low coolant light came on the other day. Nothing was leaking so I replaced the sensor. The other day, the light comes on out of now where?? How likely is it that the computer is messed up?? I had the happen with another hypertech chip however the Check engine light came on?? This is nuts

BoostedDSM

iTrader: (6)

Open loop the car runs good, when it gets up to temp it goes closed loop and uses the o2 sensors then it stats acting up. My car did the same thing, had a small misfire and utterly **** mpg. Had a bank 1 o2 code, replace it with another o2 and new extensions and its fine now. Gets something like 26 mpg with gears on the highway.

WS Sick

The coolant level light does not go through the ECM. I'd say it's possibly some foulded plugs or some secondary ignition problem. Wires and plus may fix it. How old is the optis cap and rotor?

94sleeperZ

The opti is brand new

94sleeperZ

Well, I went for it. Bought a new O2.

Seemed to have worked, however I still backfires threw the intake when you blimp the throttle, and it has a fast crank no fire feel when you shut the car off for a minute or two?? I might look into that sensor on the water pump. One time i shut it off and turned it back on, the Low Coolant light came on AGAIN?? Shut it off, turned it back on, went off??? Crazy. Seems to be running better. The surging/bucking is gone

WS Sick

Are there any rips tears or leaks in the bellows between the MAF sensor and the TB?

ugod02010

when my injectors crapped out i had similar symptoms. like the heavy black smoke and bucking surging. also killed my o2 on the drivers side. have you checked them?
seems a little wierd tho that it's mostly when warm mine did it all the time. worth a shot looking at tho.