Skip at 40 MPH

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Dec 10, 2010 | 06:54 AM

deanshark

Thread Starter

Pole Position

Joined: Dec 2009

Posts: 3,278

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From: ct

Skip at 40 MPH

This is weird but it feels like it is running out of gas so I'm 90% sure it's fuel related. My '93 LS 126K will drive perfect with plenty of get up and go, or cruising under 40 MPH. If I'm at a steady speed as soon as I hit 40 - 41 it will start to buck and jump. When I hit 46 -47 MPH it will go back to normal. When I accelerate it's fine. I've done alot of searching the past couple days but can't find anything useful. I'm just looking for ideas right now b/c it doesn't bother me that much, I just don't drive in the 40s. I'm wondering if it could be the fuel filter, injectors, or pump. I haven't pulled any codes b/c the light is on for other reasons. (AFM unplugged) Any ideas?

I was just thinking, could this be the TPS? I'll pull the codes later when it warms up a couple degrees and post it afterwards.

Last edited by deanshark; Dec 10, 2010 at 07:05 AM. Reason: another thought

Dec 10, 2010 | 08:06 AM

91LS400vgb

Pit Crew

Joined: Feb 2006

Posts: 197

Likes: 2

From: NJ

TPS Check

Throttle Position Sensor is what immediately comes to mind. It's very easy to check with a multi-meter. Here is a page from the manual that might help.

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Dec 11, 2010 | 05:46 AM

deanshark

Thread Starter

Pole Position

Joined: Dec 2009

Posts: 3,278

Likes: 317

From: ct

Thanks, I'll check the TPS when I get a chance sometime next week. I haven't had a chance to pull codes yet but, like I said, it doesn't bother me much. Thanks for that page. I have a manual but it's in storage right now so this page will help.

Dec 11, 2010 | 10:22 AM

hobojoe

Lead Lap

Joined: Apr 2007

Posts: 663

Likes: 1

From: CO

Had almost the exact same happen to me, at pretty much the exact same speed also. Turned out to be 2 bad spark plugs, replaced them all and hasn't done it since.

Dec 11, 2010 | 11:54 AM

deanshark

Thread Starter

Pole Position

Joined: Dec 2009

Posts: 3,278

Likes: 317

From: ct

Quote:

Originally Posted by hobojoe

Had almost the exact same happen to me, at pretty much the exact same speed also. Turned out to be 2 bad spark plugs, replaced them all and hasn't done it since.

The plugs are pretty new (about 3K miles) but ya never know, I'll pull them and check those when I get time next week.

I just pulled the codes and all I got was 24 (Intake air temp. sensor signal) and 31 (Air flow meter signal) Those are there b/c I have the AFM unplugged, which I know is bad. It's been like that for a long time (I just keep putting off fixing it) but these new symptoms just popped up about a week ago.