Tune up

Booboo

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1997 GT 4.6l. I just replaced all the O2 sensors, plugs, wires and coils. It still isn't running right. It is running a little rough and sluggish. It hesitates a little when floored. There are no check engine lights, no codes. Any ideas?
 

RAU03MACH

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Check your mass air flow
I had some what of a problem like that
Don't ask me how a Wal-Mart bag got in partially
And blocked some of the air coming in
Thats what happened to me
You never know and it never gave me a code

Mabe the tps cleaning your throttle body
 

RAU03MACH

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the chains stretched and guides are worn out it could be many things
thats where trouble shooting come into play
 

OpalFrostGT

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Personally, I make a list of prospective faults. Then I begin investigating by performing the easiest to do first. I have discovered that this approach saves me time and almost always leads the the "solution" . I believe Neuron has a good suggestion! I clarify...how could leaning the MAF sensor and throttle body (if preformed properly) be wrong?
Good luck and please let us know your solution!
 

ttocs

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over the past 5 years I have found more and more problems with the harnesses going to the sensors. It can be hard to find these problems if you do not have a pc hooked up to monitor live data, what your left with is to go and start the car and then push/pull/twist/pry on every harness you can find and see if when you do it if the engine changes at all. Be sure to do this when the engine is up to temp and everything is hot because one of the harnesses I found that was bad was only when the motor was hot. If you have any harnesses that have broken clips on them, replace them.........
 

Michael Plummer

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Troubleshooting a vehicle online can be tough because you have to assume so many things. Is the troubleshooting on the other end being done correctly? Is the advice you're receiving helpful? You have to assume other systems are functioning correctly. And are quality parts are being used. With that said, I would make sure the following tests are in the normal ranges.

1. Engine compression
2. Cylinder leak down
3. Smoke test for vacuum leaks
4. Cooling system is functioning properly

An engine needs four things to run: Find out which one you're missing and concentrate your efforts there.
1. Air: No major restrictions on the inlet side of things. All couplings are tight and on correctly?
2. Fuel: Fuel pump, fuel pressure, and injectors ok? Gas is fresh and the fuel tank is in good working order?
3. Spark: Are all ignition components operating as they should? Do you know how to test? Are you using quality components instead of the lowest buck option (which seems to be a favorite among some owners)
4. Compression: If the compression is in the normal range you're good.

The 5th thing your engine needs to run is Engine Management. Were any modifications done to increase air, fuel, or spark at idle, and cruise? Do you have the ability to view logs, fuel trims, load, O2 reaction would be helpful but now I'm probably getting ahead of myself here. And it's ok to bring the car to a shop, or dealership if you feel you don't have the experience or tools to troubleshoot it yourself. Better to fix the car than have it sit because it sucks to drive.

Good luck
Michael Plummer
 
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