95wannabe

iTrader: (20)

I really hate jumping on here asking "why is my car bogging under moderate throttle" but i'm just looking for some " first thing that pops in your mind" type of answers.
I just drove my son-in-laws completely stock 02 SS w/165,000 miles, from Washington DC to Albuquerque NM over the last 3 days. For you military folks, yes thats Andrews to Kirtland. I have no tools and am flying back home Saturday.
Soon as I crossed in to N.M. as I let off throttle to take the usual state line picture, it died as I put the throttle back down. Running around 75 mph at the time, I steered to right lane thinking I have to get this off the road, and 5 seconds later it came back to life. Called my in law who was in front of me, we pull over and look it over. Nothing obvious under hood. I take off again, its sputters a few times as I'm shifting thru the gears, then seemed to run ok once up to speed. Then a few minutes later, while cruise was at 75, pulling up a hill, it died again. was almost completely off the road and came back to life again. I babied it the next 100 miles running about 65. If I was more than slightly on the throttle, it started sputtering. If I ease the throttle, I could run 65-70. Any faster than that, or a hill that required more throttle, it would die.
My first thought was fuel pump. The longer I drove it, fuel filter. I don't know, What do you guys think?

LS6427

iTrader: (2)

When it died....do it cut off instantly....or sputter and shut off....?

Do you have an SES light....?

My thoughts.....failing 02 sensor(s). Won't always give you an SES light. Very easy to change with one crescent wrench....and getting the front end up in the air a little bit.

It takes 5 minutes to change one.

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LS6427

iTrader: (2)

Its best if you can get a scan at a shop just to see how the 02 sensors are switching.....to confirm this. Most shops will scan you for free, some might charge $20-$30. Around South Florida its free at most places.

If it is a bad 02 sensor.......go to a PepBoys or Advanced Auto and buy 2 new FRONT Denso brand 02 sensors. Get OEM parts numbers if you are stock.

PepBoys or any shop can put them both in in about 15 minutes....so don't let them rip you off on labor.

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95wannabe

iTrader: (20)

At speed...it seemed to cut off abruptly.
When we got off the Interstate and was moving slow, it would be running rough and died on me at a stop light. Started right back up, ran rough, I revved it a couple times, then it was fine till I took off from the light again. Anything more than light throttle, it was bog, run rough till I let off.
SES light had shown for about an hour while he was driving it 2 days ago. We been switching vehicles and it was never on when I was driving it. Or with him either

95wannabe

iTrader: (20)

I have one of the OBD2 bluetooth plugins at home. My wife is flying in tomorrow, I'll have her bring it. I can download Torque on my phone. We'll see if that tells us anything.
This sux being 1800 miles from home and having a problem.
Thanks for your suggestions so far

LS6427

iTrader: (2)

The tool needs tpo be able to read how the 02 sensors are switching while the engine is running after the engine is at full operating temp.

If an engine shuts off instantly it can be a failing Crank Shaft Position sensor...but they do not cause bogging and rough running.

If it starts bogging....then you give a lot of throttle, does it take off? Or does it bog worse?

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95wannabe

iTrader: (20)

bogs worse. I think it would shut off if I let it.
If I let off the throttle, it comes back to life

LS6427

iTrader: (2)

I think one of your 02 sensors is dumping massive amounts of fuel. How was the MPG since this started...? Usually when an 02 sensor(s) is failing it'll cut the gas mileage in half.

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LS6427

iTrader: (2)

Oh....does it also do it when the engine is cold?

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95wannabe

iTrader: (20)

Just started this in the last 100 miles of the trip. Its been sitting about 2 hours now. My son in law just drove it to the store. We'll see what he says when he gets back....its just across base.
We didn't check mileage but he did keep most of the receipts. Off top, I'd say no, gas mileage didn't change.

95wannabe

iTrader: (20)

I guess I can't say if mileage changed if whatever happened did so in the last 100 miles. We didn't think to try and fill it up again. We were just worried about trying to get here.
They're just moving here this week.

95wannabe

iTrader: (20)

ok, it ran perfect. Now he could hardly get it in 3rd gear here on base, but moderate throttle 1st & 2nd and ran fine.
Why did you ask if it ran different cold?

LS6427

iTrader: (2)

Sorry for the delay.....I'm over here in the Middle East and I had to go to sleep last night, it was like 5am.

When you start an LS1 when the engine is cold, the 02 sensors are not controlling anything. They do not come into play until the coolant is ABOVE, I believe 122*F, so only the MAF sensor is controlling fuel metering. It takes a good 5-10 minutes to get the coolant above 122*F.

If it did not act up when it was cold.......thats another indication that its MOST LIKELY a bad 02 sensor(s).

Because after the coolant passes 122*F, then the 02 sensors become active and they control all fuel metering during normal to medium throttle driving and the MAF does nothing. When you go Wide Open Throttle....after the coolant is passed 122*F, then the MAF will also come into play, and along with the 02 sensors they will BOTH work together to meter fueling, as long as you are at Wide Open Throttle.

I think you found your issue.

BUT....I still think you should get a scan to confirm its the 02 sensor(s) not switching properly, before spending money to buy new ones. WHY...because these cars have so many weird things that can cause these issues you're having. Just so you don't waste time and money......

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RPM WS6

iTrader: (3)

Definitely hook up a scanner, look for pending codes or any stored faults.

It sounds like it started up OK after dying, but that still doesn't entirely rule out a fuel pump issue. I'd recommend a pressure test, also under load if it looks OK at idle. Look for 58-60psi under all conditions, including loaded WOT.

You may also be experiencing a weak/failing injector(s.) I'd want to watch misfire counts and fuel trim data on a scanner while the rough running is happening.

Something simple....how is the air filter? Such a long trip might have resulted in a blockage (especially if it was already old), and/or if it's a K&N style it might have finally sprayed enough filter oil on the MAF to cause issues. So an MAF and air filter inspection would be in order as well.

LS6427

iTrader: (2)

But, he said it runs perfect when its cold.....none of those problems are present when its cold.

But like I said...it could be a million things.

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95wannabe

iTrader: (20)

Thanks for all the ideas so far guys ... My plugin will get here later today and I can at least see what if any codes are set. Too many things going on here to have a car issue too. I'll update as soon as I can.
Thanks again, I appreciate the help. LS1TECH is a good thing.

Game ova

TPS sensor.......

RPM WS6

iTrader: (3)

That fact doesn't entirely rule out any of those other suggestions, other than a physical blockage/clog at the air filter. Heat/additional run time may bring on issues with any of those other components.

Fuel trim, misfire and DTC data would give a better picture and hopefully point in a certain direction.

95wannabe

iTrader: (20)

My plug in was damaged in shipping, so we run to AutoZone and they pulled a P0170. If I remember right, it was labeled as a LEAN condition. Does that make sense?..Can this code be reported as LEAN or RICH?

Ls1Ryan2002

I will be following this thread, curious to see what it may be.