Engine rough idle?

The p0131 is 02 sensor, bank one. I can say the sensor is probably faulty. this guide will walk you through the steps of replacing it.

P0300 is a random misfire, how long since a tune-up. Check the guides below

https://www.2carpros.com/articles/how-to-tune-up-a-car-engine

and

https://www.2carpros.com/articles/how-to-tune-up-a-car-engine

Please run down these guides and report back.

Thanks for the reply. Tune-up was done approx 1,000 miles ago. However, fuel filter has never been replaced. Would the o2 sensor code be caused by the random misfire (or vice versa)?

The random misfire may have caused the other code.

Ok, so what should i do to check the random misfire on random cylinders?

also, i believe the heat issue is related to a low coolant level. Thanks

Below is the flow chart for p0300.

I did see a couple of tsbs for that code. The possibilities are just about endless. One tsb was for a problem computer ground, G103 I believe. You take the ground loose, check the wiring, use a file or something and shine-up the contact surfaces. G103 is located, right rear of engine block. The other tsb was for water getting into the fuel system, caused by the evap harness, vacuum lines.

Ok well I jus bought a used pickup and the main problem only occurs when I'm in drive, when I'm in park it doesn't do it. But if I'm at a stoplight or stopped when I'm in drive it will idle really rough and act like it's gonna stall and it has a couple times and when the light turns green and I accelrate it also acts like it's gonna just stall and it also has stalled a couple times. Another thing is when I'm goin up a hill it sometimes has a hard time shiftishiftishifting. Another thing is when I go to start it it sounds like the batteries dead but it starts and when it does start it makes a cranking sound like I turned the key when it was already running. What could be my problems?

is the check engine light on???

I would start by checking the fuel pressure. the battery needs to be load tested as well.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

let us know

Roy

No the check engine light is not on. How do I check the fuel pressure, and can I jus take it into AutoZone to get the battery load tested? What are you thinking I would need to buy to fix it if it's the fuel pressure. And does it sound like I need a new starter when I turn it on and when it turns on it makes a cranking sound like I turned the key when it was on already?

yes, they will do a load test for free for you. they will check the alternator and starter draw as well.

you can rent a fuel pump pressure tester there as well. there is a valve on the fuel rail to check the pressure. if it is low, the fuel pump will have to be changed.

Roy

Alright i will get on that after work tomorrow. Thanks!

Starts fine when cold, hard to start when warmed up. Rough idle. Started with bad cat so I had it fixed rough idle still present new code indicated that coils #3 and 4 misfiring. I replaced 3&4 and all wires and plugs. still idles rough. New code is p0300 random misfire replaced Mass airflow sensor and still has a problem. the engine is strong, fuel pressure and lines are working at optimum. I used OEM ACdelco spark plugs and wires and were pre-gapped at .040 Autozone insists gapping is correct even though they are not iridium plugs. could the rough idle be from a bad PCV or EGR? This truck has always been smooth, I always use full synthetic averaging 35k miles annually and tranny is still buttery smooth on the shifts. At speeds no loss of power and rides like new.

check fuel pressure with a gauge 55-62 psi auto parts rent it. then have a pro check maf and freeze frame

Thanks Hmac300. The fuel psi is at 60 fuel pump is 2 yrs old ( checked by shop ) I'll take it back and ask about freeze frame. If there is anything else you can suggest that would be great.

I am not a mechanic by any means but can handle some very small tasks under the hood, but when my 2000 Silverado developed a miss while sitting at a stop light or while in park and became harder to start I figured it needed new spark plugs. While changing the plugs I damage one of the plug wires so I also installed a new set of plug wires. Much to my disappointment that did not solve the problem. Figuring this problem is out of my league I took it to a nearby mechanic. He hooked it to his computer and found that 2 cylinders were misfiring and sometimes a third. Since I had changed the plugs and wires they went to swapping some of the coils around to determined if they were the culprit and found that they all were working properly. Next they figured it was in the wiring or the computer. The owner (which has a good reputation in town) then went through the entire wiring system found nothing wrong but still added a ground to the computer. After that did not help we decided to change the computer. Once the new computer was programmed and installed still nothing. I don’t know how to explain my disappointment, but it is huge. The mechanic now thinks it could be the fuel pump. They checked the pressure and it was just two pounds shy of being normal. At this point I don’t know what to do. I know the pump will be around $300 to $400 plus labor. Should I continue to let them take jabs at it? Can you help me?

try installing a new cap and rotor. It might have corrosion and not letting it create enough spark. hope this helps vote for me please

Stay with them, they have the pressure to perform. You need to talk to them about making some concessions for mis-diagnosing. They should at least take the labor and part mark-up back if they are in the wrong. And be willing to take more responisiblity if the the fuel pump doesn't solve it. I don't have the results of testing so only he can answer that.

If you don't get satifaction, go to his boss and explain the situation and what you want.

My chevy silverado 1500 with 5.3L v8 has service engine light and p0300 (random eng misfire) and p0131 (o2 sensor- bank 1 sensor 1). the truck idles rough sometimes and at times the check engine light flashes while at an idle and idle gets even rougher. I have changed the plugs and wires, ran seafoam through the brake booster vac line, and still nothing is helping. The truck also has an extremely strong exhaust smell. Any help is greatly appreciated!

P0300-normally caused by vacuum leak and a bad MAF

Engine running rough or misfiring can be cause by the following:

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

let us know

how can i find the vacuum leak or test to see if there is one?

Listen to a hissing sound around the intake manifold/throttle body and vacuum hoses you can use a vacuum gauge or follow this guide.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Please run down this guide and report back.