98z71 5.7 multiple misfire P0300 fouling 1 3 5 7 plugs with gas what causes ths

only on that side... try and go up 2 heat ranges on that side,,,and / or first .. take some good pictures of those plugs and post them...

Possible causes po300:... - Faulty spark plug (s) - Faulty ignition coil (s) - Clogged or faulty fuel injector (s) - Intake air leak - Fuel injectors harness is open or shorted - Fuel Injectors circuit poor electrical connection - Ignition coils harness is open or shorted - Ignition coils circuit poor electrical connection - Insufficient cylinders compression - Incorrect fuel pressure Tech notes The P0300 code means that a cylinder(s) is misfiring or is randomly misfiring. Start by checking for intake leaks, intake gaskets are common caused of multi-cylinder misfiring. If no leak are found the next step is to replace the spark plugs. If the problem persist more tests needs to be done to diagnose problem,

Replace plugs wires dis cap n rotor button still doing same thing

Check for vacuum leaks, that is a Vortec engine, intakes are prone to leak, check the bolts, there are only 8 of them, torque to 15 to 20 ft.lbs. They say 12 ft.lbs. but that is pretty light.

Check all that n leaks on intake

By chance did you use carburetor cleaner? If there is a vacuum leak spraying the carb cleaner would make the rpm rise. If still all good then you are going to have to dig into it to find the problem. How many miles on her? Compression test may be in order. After that or you could do first is get the coils checked. I would check the electrical connections to the injectors also.

Compression is good has little over 100000 on it have checked ll connection s injection all good fuel pressure is correct

Only has the one coil pack could it cause it to misfire n foul plugs on one side

Well yes, that can be tested, I believe Auto Zone can. But I know I have looked on line on how to and what specs to look for when testing a coil, but you would need a volt ohm meter.

I have a 96 chevy silverado z71 4x4 extended cab only has 97,000miles.. motor 5.7 ...service light starts to flash for about 20 seconds then stays on comes up as a #5 misfire ive changed plugs and wires but it didn't fix still comes up #5 misfire

Change cap rotor oil oil filter check all vacuums replace fuel pump still missing misfiring number 5

Can someone tell me how to fix a p0300 misfire on my 97 z71 5.7 and it will back fire

Hi Guys, you all had great understanding of what parts are generally needed to get a basic Chevy v8 or even a v6 ignition generic components. But in figuring out the Vortec engines it seems evrybody forgets the little thing we call “the crankshaft ignition sensor” ; this is a very important sensor as it tells the distributor exactly where it is in relation to the “dizzy” and camshaft. On the 1996-1999 chevy/gmc vortec engines both v6 and v8 are located in the front of the timing cover just right of crank but behind the vibration dampner weight. I’m not sure on the “big block” vortec engines ; although I have heard rumors that it may be located at the right side of flywheel area requires the starter to be removed( I’m not sure only relaying what is in the gossip of other gearheads)

Would a clogged cat. Cause a p0300

Cleaning out the cat. did not help in my case. I have a 2002 3500 motor home that the engine will simply lose power and die. I have tuned it up, changed the ECM, cleaned out the converters, changed the #7 coil pack and nothing has helped. I'm open for any other suggestions. Rick

No one has tried pulling ignition module and have tested 97 is located on the mount for the coil pack just a suggestion