[jgilbank]

I have a 99 Chevy Silverado with the 5.3L V8 engine.
What does cade P1301 mean? And how would I fix it? What part does it need?
Thanks Jim

[TxGreaseMonkey]

Apparently, you are getting a misfire in cylinder 1. If you have not replaced the spark plugs in the last 50,000 miles or 3 years, I'd recommend that you do so. Only use the exact ACDelco plugs that came in the truck. Be sure to apply a light coating of dielectric grease to the porcelein portion of the plug and the top electrode. The dielectric grease helps prevent misfires. Using a flux brush, lightly coat the threads with anti-seize compound.

Afterwards, clear the old code with a code reader. If the code returns, try replacing the coil to cylinder 1.

[jgilbank]

Apparently, you are getting a misfire in cylinder 1. If you have not replaced the spark plugs in the last 50,000 miles or 3 years, I'd recommend that you do so. Only use the exact ACDelco plugs that came in the truck. Be sure to apply a light coating of dielectric grease to the porcelein portion of the plug and the top electrode. Using a flux brush, lightly coat the threads with anti-seize compound.

Afterwards, clear the old code with a code reader. If the code returns, try replacing the coil to cylinder 1.

Thanks - This makes a lot of sense. There's a lot of miles on it now and it just not running like it use to and it been very gradual.
What your opinion of these new E3 - Diamond Fire Spark plugs compared to the AC Delco? As good or stay away from? (3:16 forever - what a great ministry PTL) Thank you, Jim
Thanks Jim

[TxGreaseMonkey]

Thank you!

Only use the same ACDelco spark plugs that came in the truck. Cross-reference spark plugs, especially those with differing spark plug gaps, often cause misfires and codes to be thrown.

[jgilbank]

Apparently, you are getting a misfire in cylinder 1. If you have not replaced the spark plugs in the last 50,000 miles or 3 years, I'd recommend that you do so. Only use the exact ACDelco plugs that came in the truck. Be sure to apply a light coating of dielectric grease to the porcelein portion of the plug and the top electrode. Using a flux brush, lightly coat the threads with anti-seize compound.

Afterwards, clear the old code with a code reader. If the code returns, try replacing the coil to cylinder 1.

Thanks again, regarding the AC delco plugs only - Will do!

[TxGreaseMonkey]

Let us know if the new plugs solve the problem.

New plugs should make a big difference. Also, I'd recommend using SAE 5W-30 full-synthetic engine oil and changing the transmission fluid and filter with Mobil 1 Multi-Vehicle Synthetic ATF. I've helped a lot of ranchers in Texas make the switch on their trucks and they are grateful. If you take care of the engine and transmission, everything else that can go wrong is relatively minor.

This link may help you with the transmission:

https://www.askmehelpdesk.com/cars-t...ml#post1873132

[jgilbank]

Hello Texas Grease Monkey
Okay, I have put new plugs in and wires (cause I broke one changing the plugs) but in colder weather it turns over well on the first try of the command start but won't keep running until the 2nd try. It started first time every time last winter. Could this be the Mass Air Flow Sensor?
Would cleaning help?
Thanks for your help, Jim

[TxGreaseMonkey]

Cleaning the MAF Sensor with MAF Sensor Cleaner may help:

https://www.askmehelpdesk.com/cars-t...ml#post1377134

It might also help to clean the Idle Air Control Valve, throttle plate, and throttle body. Afterwards, clean the air box and replace the air filter. Be sure to clear the old code with a code reader. Add a bottle of Chevron Techron or Shell Regane to the gas tank.

If the problem persists, consider replacing the Engine Coolant Temperatue (ECT) Sensor, which affects fuel injector pulse width. The ECT Sensor is a temperature dependent resistor (thermistor), whose resistance decreases as the engine coolant temperature increases. It provides a richer mixture when cold, leaner mixture when hot. They become corroded, due to not changing the coolant frequently enough.

[TxGreaseMonkey]

Did the new ACDelco spark plugs solve the misfire problem?

[jgilbank]

Did the new ACDelco spark plugs solve the misfire problem?

Yes, when the engine is warm, you can definitely tell that it starts stronger and faster and it has a faster response on the gas peddle.
I like your idea about the ECT sensor.

Now could this be related, I have one other problem. My engine light is on and my analyser tells me it's the code 420 catylis emmissions so I've replaced both O2 sensors on the drivers side but still the engine light comes on after say 5 to 10 miles? Just thought you should know that as well - and thanks so much for your great help with this.
You are blessing my friend.

[TxGreaseMonkey]

Once it warms up and comes out of "open loop" mode, the CEL comes on. It sounds like the catalytic converter is bad, which may be causing the "down stream" oxygen sensor to throw a code.

[TxGreaseMonkey]

It wouldn't surprise me if the sole problem is the catalytic converter. It may be negatively affecting injector pulse width, when the engine is starting. Open loop control is not precise enough, since the converter is bad.

[jgilbank]

Once it warms up and comes out of "open loop" mode, the CEL comes on. It sounds like the catalytic converter is bad, which may be causing the "down stream" oxygen sensor to throw a code.

Now I did get a muffler shop to weld in 2 new catalytic converters a little over a year ago? So I would think they should be working fine?
I will try the ECT and Clean the MAF senser and watch some more.
Thanks again,
Jim

[TxGreaseMonkey]

Keep us posted.