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Discussion Starter · #1 ·
I have a 97 T/A 107,885 on the clock it has developed abnormal fuel trims the cheap scanner I have says my Ltft1 is 25% and my Ltft2 is 50% this is at idle also its reading 3.2 under load. it is super rich u can literally smell the gas coming from the exhaust its had the EGR deleted, Lt headers, CAI and the o2s are relatively new im no mechanic so any help diagnosising this issue would be greatly appreciated also im new to the fourm so hey everyone
 

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Was the pcm reprogramed for the long tube headers? If no, it needs to be. Here's a link to a good lt1 tunerwww.lt1pcmtuning.com

Next is to go back and scan again. While running pay attention to pre cat O2 readings. They should be jumping above & below the 450mv center line on a regular basis.

Put a fuel pressure gauge on fuel rail. Do key on prime. Pressure should be around 43 psi. Start engine and idle it. Pressure should be in mid 30's psi with vacuum line removed and blocked from pressure regulator. Drive car with gauge taped to windshield. Except for idle pressure should maintain at about 40 psi. If your pressure is too high, that can cause an over rich mixture.

Have you replaced the fuel filter & air filter? If no, do this.

You might need to check for clogged fuel injectors. This involves pulling fuel rail up & out of engine, high enough that you can see injectors spray. Have assistant crank engine while you watch for a good injector spray pattern.

ALWAYS have a FIRE EXTINGUISHER on hand, just in case. Have catch cans under each injector to catch fuel. And disconnect coil wire from coil. We don't want you burning yourself, or car up. Also when injectors are pulled out of engine, you will need new o-rings.

Finally, heres a link to 96 factory service manual. Your 97 will share 99% of info with 96.www.mediafire.com/?40mfgeoe4ctti
 

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I dont know if it was ever tunned. previous owner did the mods it has ran perfectly for the last year other than the clutch which i replaced along with the front 2 o2 sensors about 4mts ago the trailing o2 sensor has been deleted due to the off road y pipe im assuming the car has had a tune because like i said it ran fine. (good enough to spank a few mustangs lol) but all of a sudden I was cruising about 70 on the hwy and it started bucking and spitting it was raining pretty hard so I assumed the opti may have gotten wet but it only starts acting up when in CL the o2s are definitely not reading properly if there supposed to be around 400 iv only got arond 200 on bank 2 bank 1 seems within the specs u mentioned thank u for ur help im lost and dont have money to throw parts at it im borrowing a fuel pressure test now
 

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I'm not used to that particular sensor category. But 3.5% load would be about right at idle. Try opening throttle up slowly and see if load % increases with throttle opening.

If a before the cat O2 is not jumping around over & under the 450mv mark, there's something wrong there. A stuck O2 can be caused by a wiring problem between O2 and PCM. Use the wiring diagrams for lt1 fuel injection in manual to trace O2 wiring.

Did any codes come up when you scanned car? Opti codes & ICM codes do not light the SES.
 
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