Vette running rough

Reply Subscribe

Thread Tools

Search this Thread

Mar 7, 2005 | 02:08 PM

The Vette

Thread Starter

3rd Gear

Joined: Mar 2005

Posts: 3

Likes: 0

Vette running rough

Hi Guys,

I'm hoping someone can help me:

I've got a 99 manual Coupe with headers/cam and its started to act up the last couple of days. I ran the codes and got:

P1133 Heated Oxygen Sensor (HO2S) Insufficient Switching Bank 1 Sensor 1
P1153 Heated Oxygen Sensor (HO2S) Insufficient Switching Bank 2 Sensor 1

I also get occasionally the P0300 Engine Misfire Detected and can hear a misfire. The car doesn’t always misfire but its really jerky when you hit the gas virtually all the time, its like its hesitating.

My question is would the O2 sensors cause the car to run really bad and a misfire? If not could it be anything else, I know there is a slight leak in my exhaust but apart from that she is ok.

Thanks in advance for any help

Mar 7, 2005 | 02:27 PM

FASST LN

Drifting

Joined: Jan 2000

Posts: 1,660

Likes: 9

From: Charlotte, NC

I would check your plug wires and possibly switch out your spark plugs. It is possible that enough misfires has resulted in too much raw fuel going down your exhaust and fouling out your O2 senors. You might have to purchase new O2 sensors as well.

This is just a guess.

Mar 7, 2005 | 04:32 PM

70T/A400

Racer

Joined: Nov 2004

Posts: 423

Likes: 76

From: Oshawa

It may be that the Oxygen sensor is either fouled with silicon, lead, or it is not functioning in a hot environment. The oxygen sensor will cause the symptoms you describe. Try taking the front sensors out and heat them with a propane torch-this can help temporarily. Let us know what your gas mileage is as well. Good luck,

Glen

Mar 7, 2005 | 06:36 PM

BanditDude

Drifting

Joined: Aug 2004

Posts: 1,799

Likes: 1

From: Dayton Ohio

Quote:

Originally Posted by The Vette

I know there is a slight leak in my exhaust but apart from that she is ok.

IMHO, a significant leak in front of the sensor could make the computer think it is running too lean. The resulting rich mixture might explain your drivability issues.

Good luck!

Mar 7, 2005 | 06:45 PM

Bill Curlee

Tech Contributor

Joined: Dec 1999

Posts: 32,910

Likes: 2,402

From: Anthony TX

CI 6,7,8,9,11 Vet

St. Jude Donor '08

If you have mis-fires, you MUST correct that issue FIRST!!

Remove the wires and inspect them. Look for corroded terminals, burnt, torn, cracked or damaged insulation and boots. OEM wires should read between 250 - 750 ohms. If you have high resistance, tyash the wires and get new ones!!

Here is what a bad stock wire looks like:

Change your plugs out! Look for fouling, crack/damaged insulators:

Once you have the secondary ignition squared away, clear the codes and take it out for a good hard run!! I bet ya a cold one that your problem is GONE!!!!

Bill Curlee

Mar 7, 2005 | 07:20 PM

pewter99

Team Owner

Joined: Dec 1999

Posts: 174,312

Likes: 1,217

From: Here

Pilot of Beer Force 1

Tampa Regional Coordinator

CI 4-5-6-7-8 Veteran

Organizer St. Jude Fundraiser

I believe in the Beer Fairy

Check the clearance between your plug boots and your headers as well...mine weren't touching but were close enough to arc thru and cause a helluva miss..

Mar 9, 2005 | 01:59 PM

The Vette

Thread Starter

3rd Gear

Joined: Mar 2005

Posts: 3

Likes: 0

Cheers for the replies guys.

Took the car to a friends shop yesterday, we fixed the zorst and took it off the ramps and was still running rough. Looked over engine and noticed air intake had come off just after the MAF sensor, put it back on and it stopped the jerking and car ran fine.

However still got the O2 codes and misfire code this morning, its intermittent and car runs ok. I'll take the leads off and inspect them this weekend, just had new plugs so they should be ok.

What confuses me is shouldn't the P0300 code have been deleted when the cams were done, it hasnt appeared before. Can disconnecting the battery for a while cause the code to come back or is it a case of the code was deleted in relation to the cam but if say a coil pack failed it would still detect a misfire?

Thanks again

Mar 9, 2005 | 04:06 PM

Bill Curlee

Tech Contributor

Joined: Dec 1999

Posts: 32,910

Likes: 2,402

From: Anthony TX

CI 6,7,8,9,11 Vet

St. Jude Donor '08

If you had a P0300 mis-fire code, the engine is detecting one or more cylinder misfires! You really need to check those wires. they get damaged easily and sometimes are broken on the inside. The internal conductor is a spirial wound wire on an amirid core. When yoy read the wire end to end, that is what you are reading. it should be 250-750 ohms. When they are bad you normaly see readings in the MEG OHM range!

The old resistor carbon core wires that are found in most cars do not really have wire but use a carbon impregnated plastic core which usualy runs any where from 2000-3000 ohms per foot.

I would guess that one of your wires is BAD.

BC