Did you forget to reconnect the coolant level sensor after installing the new reservoir?

Ah, the DIY camera connection to the ECU circuit – now we’re getting somewhere! 😂

Your tests indicate that the bearings are worn. You can drop the pan/sump and take a look. Check the condition of the top end by performing a compression test.

You often have owners who are obsessed with changing the oil, forgetting about the oil filter.

Re-posting original post as OP deleted account.
2000 Honda Accord 2.4L manual transmission.
Was driving it home when it started misfiring. Systems are bucking, losing power, flashing check engine light once I got to the mountain to get back to my house, it lost all power. After letting it sit on the side of the road, I was able to get it back home. Ran the codes, it’s giving misfire on all cylinders. Here’s what I’ve tried:
New spark plugs New wires New distributor Conducted compression test (all good) Conducted fuel pressure test (all good) Checked valve lash Checked timing (new belt, not out of time) Tested MAP sensor (testing good, but who knows) Sprayed for vacuum leaks
I’m at a loss here. Now, when you start it cold, it will run for a few seconds, then sputter out and die. Once it warms up, it will idle fine, but will not rev. If you spark some starter in the air box, it will rev right up, which I think is interesting. Could that mean fuel issue? Any ideas would be helpful!

The culprit is a car gremlin that has taken up residence in your car and is playing tricks on you. 😂

Seriously, it’s probably a faulty Headlight Control Module. Refer to the car’s diagnostics and wiring manuals.

Have you attempted to retrieve diagnostic trouble codes from the ECU?

As you’ve summised, the fault appears to be related to the temperature of the engine. IIUC the engine starts ok when cold or hot but not when warm.

Input from the engine temp sensor plays plays a role the air fuel mixure that is set by the ECU when starting the engine. Your car being ~16 years old, is it still on it’s original temp sensor?

When starting with the engine cold, the ECU sets a rich AFR before it switches to closed loop operation when the O2 sensor heats up to operating temp.

Look online for a copy of the workshop manual for your car as it will contain diagnostic test section for ‘hard start/long crank’. It will also contain info on how to test the temp sensor.
Hope this helps.

Thinking of the days when cars used be be sold with a spare? 🤔

You’re welcome. Best to search/post on the Honda/Civic forums. Your fellow Civic owners are the best people to advise you.

The engine/ECU has 2 modes of operation; Closed Loop (rpm = idle – ~3.5k) (sensors) and Open Loop (rpm = >3.5k) (map).

Your mods (O2 sensors) may have impacted the closed loop mode of operation. Try searching the mustang forums with respect to performing a de-Cat for your year/model.

You don’t need to rely on the dealer/workshop for codes – suggest you purchase an inexpensive reader and learn to retrieve the codes yourself. If there are no trouble codes then the fault may lie with the CVT auto transmission which like the engine is computer controlled.

Crowned as the “Most Accurate Tire Gauge” by BestReviews in 2023 - Not any more! Ya gonna have to subtract 11 psi from all measurements. 😂

Who replaced the cats and where did they source them from?

I’ve seen cars with old cats where the internal metal brackets that hold the substrate in place have rusted away allowing the substrate to break up. Cats can suffer internal damage when they get hit with something hard, like when you run over a rock. An engine under load will usually produce sufficient exhaust gas flow to shift the pieces around inside the cat.

No-load test for a busted cat - Rev the engine in neutral, really floor and pump the pedal to maximize the flow through the exhaust system. Perform the test when the engine has been running for while - the engine and exhaust are hot. If you hear a rasping or rattling sound coming from underneath the car as you ease off the pedal - it’s likely to be a busted Cat.

Congrats for having the courage in attempting one of the trickier DIY car maintenance tasks. As a young guy, I didn’t get it right the first time either. Review your procedures and method with a view to figuring out how air got into the system and bleeding the system correctly.

You need to be careful not to open up the bleed valve too much as air will enter the system via the valve. So try to open it up a tiny bit at a time, just enough to allow fluid to flow. You also have to co-ordinate well with the assistant depressing and holding down the brake pedal. Keep checking and topping up the reservoir. Tip: when doing flushes, purchase a different color fluid to the existing fluid in the system so that it’s easier to tell when the old fluid has been fully purged when bleeding. Hope this helps.

I would test the suspect relay on the bench using a 12VDC power supply. Again, you can improvise by using the car’s battery or a cordless power tool 12V battery pack. Check youtube - How to test a 12V relay.

Auto electricians use a special adapter to perform in-circuit tests. The adapter fits into the relay socket and the relay itself fits into the adapter. This allows voltage and current tests on the relay’s control and load side circuits.

2 years is a long time to be driving with the battery warning light on.

An ideal tool to use would be an automotive stethoscope. Maybe you can improvise.
Once you’ve identified the relay, examine the vehicle wiring manual to see which circuit energizes the control side (coil) of the relay.

Is your loss of power steering while driving related to this?
According to Ford, a potential intermittent electrical connection in the steering gear of some Ford Explorers may result in the loss of Electric Power Steering Assist (EPAS) while driving. This could cause the steering system to default to manual mode, making the vehicle more difficult to steer, especially at lower speeds.

Check with Ford technical support. Do you have an itemized account of both labor and parts on what work the repairer actually performed on your car. You need to do some research on this to see if you can present a case of misdiagnosis to the repairer.

Look for a 12 volt charger with Auto-polarity detect and over-charging protection. Auto-polarity detect means that no damage will be done if you accidentally get the charger to battery connections wrong.

You could have a bad electrical connection from the battery to the starter motor. Check the battery ground connection to the engine block. Check the alternator output voltage - may not be sufficient to charge the battery. Consider taking your car to a different workshop.

Also when your battery is in discharged state, you should put the battery on a charger (deep charge). Cranking the engine takes a lot of energy out of the battery and going for short trips won’t be enough time for the alternator to recharge it.

Look to see if your battery has a Charge Indicator (Magic Eye) which indicates the condition or health of the battery using colour codes. e.g. Green = fully charged, Red = fully discharged, etc. The clicking sound is made by the starter motor relay and indicates that the battery is in discharged state or a bad electrical connection exists in the starter motor circuit including at the battery terminals. There’s plenty of online info explaining how to clean your battery terminals. Hope this helps.

Could be bad AFR caused by a failing MAF/MAP sensor, fuel delivery problems or restricted blocked CAT (exhaust).

A failing MAF/MAP sensor will usually be detected by the ECU and a code generated.

If spraying accelerant into the airbox causes the engine to smooth out then it would indicate lean AFR - fuel delivery issues.

Fuel injectors are very sensitive to changes in fuel pressure. A lot of early model fuel injected vehicles got sent to the wrecking yard because owners & workshops were unable to diagnose fuel delivery problems. To detect fuel pressure drops and fuel flow issues you really need to check fuel pressure under load conditions as opposed to no-load (neutral/idle speed - negligible fuel consumption). Manufacturers corrected this by installing a fuel pressure sensor to the fuel rail so that the ECU could monitor fuel pressure.

Under heavy load conditions the engine’s fuel consumption approaches MAX requiring a large amount of fuel (MAX flow rate) in which the delivery system is unable to supply, so the engine runs lean (lean AFR), hesitates, bucks or stalls. To recreate the problem under load, find the steepest hill in your area then floor the accelerator (WOT) when the car is at the beginning of the incline. Safety precautions - make sure the road is clear and there are no cars behind. Should the engine stall, may need to use a key-on/key-off sequence to allow the pump to build up fuel pressure before attempting to start the engine.

This problem will progressively get worse until it’s so bad it can be recreated under no-load condition. i.e. stationary in neutral. Try flooring the accelerator pedal in neutral. In the meantime owners need to avoid loading the engine by feathering the accelerator pedal. With the engine running lean (starved of fuel), the engine temp will run hot so keep an eye on the dash temp gauge and pull over and stop the engine should it enter the red zone.

Most fuel delivery problems are caused by a failing fuel pump or fuel regulator. Check the pump’s electrical circuit before replacing it. For DIYers, ScannerDanner has some good videos on diagnosing a failing pump including electrical circuit tests.

A mistake some DIYers make is to replace the pump and filter without checking the fuel tank for accumulated dirt and debris.