Spark Plugs

Hi:
Yes, it can be done from the top, but with much difficulty. It is easier on a rack from the bottom.

You mentioned replacing so many items but were they done because of the problem?

I asked if anything was done prior to it occurring as I need to understand the problem.
I also need o understand if any trouble codes are showing. If you need a fast answer, then you would need to have a person standing next to the vehicle to check and test it.

If I had been able to answer the question by just what you mentioned, then I would not need to ask for more details.

If no codes are showing and everything looks good, you would have to check the exhaust for clogging. The most common cause of exhaust clogging would be the catalytic converter.

Ok, keep me updated, I would like to know the cause as well.

Theres a motor mount on the front parts of the engine that goes to the front of the car. Loosen the motormounts and hook up a ratchet strap to somethign strong and put some torque on it and roll the engien forward. This give syou alot of axcess to the rear plugs

The O2 sensor and catalytic converter are 2 different thing. O2 sensor may fail and cause engine control faults but the catalytic converter can get clogged if it is faulty. You need to remove the catalytic converter to check for clogging. Test drive with it removed, though the noise would be loud as the exhaust system has been disconnected, to confirm it is not the cause.

Here is a list to check. See if you had missed anything and if none works, I would suggest going over them once again to ensure nothing had been missed out or wrongly adjusted/installed during your previous repairs/checks.

LACK OF POWER OR SLUGGISH
Symptom Definition
Engine delivers less power than expected. Little or no increase in speed when accelerator is pushed down.

Possible Cause & Correction
Check following items:
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Ensure air filter and fuel filter are not plugged. Replace if necessary. Check for incorrect fuel pressure.
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Check for proper operation of thermostatic air cleaner damper door.
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Ensure initial ignition timing is properly set.
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Check for proper operation of TCC or VCC system.
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Check ESC system for excessive retard.
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Check EST system for proper operation.
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Ensure EGR valve is not open all the time.
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Check exhaust system for restrictions, such as a damaged or collapsed pipe, muffler or catalytic converter.
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Check charging system output. Repair charging system if voltage is less than 9 volts or more than 17 volts.
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Check for A/C clutch cutout at wide open throttle.
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Check MAP sensor output.
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Using Spark Tester (ST-125), check for available secondary voltage.
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Check engine valve timing and compression.
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Check ECM grounds for clean, tight connections.
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Check for a worn camshaft.
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Check for excessive fuel additives.

Check if throttle plate is opening fully when accelerator is fully deprssed.
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Is the check engine light come on? Have you checked for weak spark and is it always the #5 cylender?

Did they check for an injector pulse? Compression in that cylender?