Please help--recurring trouble code, rough idle, misses


	Auto Repair Home	SEARCH POSTS	WHO'S ONLINE	LOG IN

Automotive Repair

Car Troubleshooting Topics
  Car Troubleshooting
  Engine Troubleshooting
  Engine Fault Codes
  Electrical and Wiring
  Transmission Problems

Car Repair Topics
  Car Making Noises
  Car Stereo Repair
  Heating or AC Issues
  Motorcycles and ATVs
  Tricks of the Trade
  Truck Repair Advice

Site Options:
  Login
  Sign up here!

Latest Forum Post

1989 toyota pickup 3.0 crank no start

I have a 1989 toyota pickup 3.0 crank no...

Strut spring orientation and strut mount tension nut

2017 Nissan rogue awd 2.5 L Put in Monro...

Transmission stuck in part, I have tried everything

So I'm working on my elderly fathers 201...

2017 dodge journey LED headlights on/off randomly

Year of vehicle 2017 Make of vehicle dod...

Kia Soul starter replacement issues!

Okay so my car is a 2010 Kia soul 2.0 en...

Please Help - Knock sound & engine fail

Hi all, Hoping to get some insight and ...

multiple warning lights

2013 GMC Terrain 130,000 miles 4 cylinde...

03 alero no low speed blower

Good day everyone, I have a 2003 Olds a...

04 Chevy 2500hd tail light issues

Help!!! I have changed my combo switch...

1999 Grand Caravan Sport not starting.

Hi. I'm new here. I hope someone can hel...

Please help--recurring trouble code, rough idle, misses,

Sign up here!

Search for (search options)

Auto Repair Home>> Automotive Repair>> Engine Troubleshooting

entropy333
New User

Jul 22, 2020, 9:48 PM

Post #1 of 3 (964 views)

Please help--recurring trouble code, rough idle, misses,	Sign In

2008 Hyundai Santa Fe 2.7 l. runs rough, check engine light on, code po300, has had plugs, coilpacks, plenum gasket, fuel injectors replaced. Also intake plenum, crank sensor, mass air flow sensor, fuel pumo, filter and regulator, and computer PCM and throttle body.Timing belt and ignition wiring checked, vacuum lines and compression checked, also leak-down tests. After part replacement, car runs okay for a couple minutes, then engine light comes back on and P0300 code returns.Please help--don't know what else to try, thanks.

Double J
Veteran / Moderator
Double J profile image

Jul 22, 2020, 10:39 PM

Post #2 of 3 (954 views)

Re: Please help--recurring trouble code, rough idle, misses,	Sign In

Well you've thrown a lot of parts at this, i assume all in an attempt to fix the P0300

Quote

After part replacement, car runs okay for a couple minutes,

after which part? any in particular or after all were replaced?

Have you checked the Lower Intake manifold gasket for vacuum leaks?
I didn't see where that was replaced,only see the Intake plenum and gasket...

(This post was edited by Double J on Jul 22, 2020, 10:41 PM)

Sidom
Veteran / Moderator
Sidom profile image

Jul 23, 2020, 9:59 AM

Post #3 of 3 (924 views)

Re: Please help--recurring trouble code, rough idle, misses,	Sign In

a P0300 is a random misfire code. This pops up when more than 1 cyl is misfiring. 1st it would help to find out which cylinders are misfiring.

If it runs good while it's cold, you need to do the compression test while it's warm and running bad.

What was the results of the compression test and leak down test?

Is there any P0171/P0174 codes stored?

Search for (options) Privacy Sitemap