lt1 sputtering
Thread Starter
Heel & Toe
Joined: Jun 2007
Posts: 17
Likes: 0
From: ward arkansas
lt1 sputtering
i have a 1996 lt1. the car runs good for a while and after driving it in normal tempature range for a while my estemated mpgs drop from 27 to 15 and it sputters on acceleration up till about 5500 rpms it smooths out then when it shifts it sputters again. any ideas?
Race Director
Joined: Dec 2006
Posts: 10,383
Likes: 4
My first guess would be a fuel filter.
Does it have any codes stored?
Is this car driven regularly?
Does it idle as smoothly as it ever did?
Have you eyeballed under the hood and checked all the normal stuff like loose hoses wires etc?
Does it have any codes stored?
Is this car driven regularly?
Does it idle as smoothly as it ever did?
Have you eyeballed under the hood and checked all the normal stuff like loose hoses wires etc?
Fuel filter,It may or may not be your trouble (good chance though) but it should be changed once a year if driven much. You also may want to have your ignition module checked.
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Your drop in MPG surely is a clue you are running very rich. Even above 5500rpm, you are probably still running rich, but it is just less noticable
The fact that it runs fine at first but then "sputters" after warmup is a clue that the problem occurs only during "closed" loop operation.....this may be indicative of a bad O2 sensor(s) which is reporting a constant "lean" condition back to the PCM. Check for error codes.
The fact that it runs fine at first but then "sputters" after warmup is a clue that the problem occurs only during "closed" loop operation.....this may be indicative of a bad O2 sensor(s) which is reporting a constant "lean" condition back to the PCM. Check for error codes.
Last edited by MikeC4; Jul 17, 2007 at 10:21 PM.
Team Owner
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From: Fort Knox, KY
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Check your ignition and coil wires, too. You might have electrical arcing. Shows up like a **** once the engine warms to operating temps.
Those HEI ingitions are very sensitive to bad wires, broken or missing wire holders and seperators, too.
Open your hood at night or in a darkened garage with your hood lamp fuse pulled and look closely for any sort of electrical creepycrawlies.
You can also mist your wires with water in a spray bottle to reveal underhood electrical gremlins, too.
Those HEI ingitions are very sensitive to bad wires, broken or missing wire holders and seperators, too.
Open your hood at night or in a darkened garage with your hood lamp fuse pulled and look closely for any sort of electrical creepycrawlies.
You can also mist your wires with water in a spray bottle to reveal underhood electrical gremlins, too.
Last edited by onedef92; Jul 18, 2007 at 11:44 AM.
