PLZ HELP: P0300 , but only at high speeds. . . - EvolutionM - Mitsubishi Lancer and Lancer Evolution Community

Notices
Lancer Troubleshooting Get help with any troubleshooting problems you may have.

PLZ HELP: P0300 , but only at high speeds. . .

Reply

 
 
 
Old Jan 18, 2009, 03:11 PM
  #1  
Newbie
Thread Starter
 
Join Date: Dec 2004
Location: Chi-Town
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
PLZ HELP: P0300 , but only at high speeds. . .

Hey all, I've got an 04 Lancer ES here. The only things under the hood that are non-stock are the K&N intake system, new battery (precautionary) and Pulstar spark plugs. Both of these were added over six months ago, and I haven't had any problems with the vehicle in the 5 years I've owned it (until now). A few days ago, Chicago hit 20 below. I had difficulty starting the car initially, but that's to be expected. I let it warm up for about 15 minutes, and drove it for about 3 miles, and hit a problem. I gunned it coming out of a turn, and it stuttered a few times, and hung around 4000 RPMs without accelerating, and the check engine light came on. I let off the gas, and the car seemed to be OK. I drove the 15 mile trip to work, and had someone read the OBD code. The code is P0300, which means random misfires. I reset the computer, and drove the car down side streets home, with no issues. A few days later, the weather was much warmer, and I took the car on the highway, after the engine was thoroughly warmed up. I drove it pretty hard up to 60 mph, and the trans was going through the gear as normal, no hiccups or anything, and I regularly topped 4500 RPMs (automatic trans) through all the gears. The problem came then, around 60 MPH. Whenever I give it a lot of gas, I can feel the misfires, and the car hangs around 4000 RPMs. If I go easy on the gas, the car accelerates as normal, no misfires or anything. I've searched the forums and found some information regarding the problem code, but I don't want to go through a lot of the replacements steps, especially since some of them don't make sense given the situation (I doubt all 4 spark plugs are bad, etc). I'm looking for any advice or ideas any of you may have. Thanks in advance. . . -Jx-
JohnnyXmas is offline  
Reply With Quote
Old Jan 18, 2009, 08:38 PM
  #2  
Evolved Member
iTrader: (18)
 
4g94T's Avatar
 
Join Date: May 2004
Location: California
Posts: 2,069
Thanks: 0
Thanked 0 Times in 0 Posts
You may have a clogged or bad injector(s)
4g94T is offline  
Reply With Quote
Old Jan 19, 2009, 05:13 AM
  #3  
Newbie
Thread Starter
 
Join Date: Dec 2004
Location: Chi-Town
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Yeah, I did think of that. I just don't have the resources to be buying random parts to see if they fix the problem. I only put mid to high-grade name-brand gas in the thing, and I ran a tank through it with some injector cleaner, but saw absolutely no difference.
JohnnyXmas is offline  
Reply With Quote
Old Jan 19, 2009, 06:15 AM
  #4  
Evolving Member
iTrader: (2)
 
oneonlywgs's Avatar
 
Join Date: Jan 2006
Location: Maryland
Posts: 269
Thanks: 0
Thanked 0 Times in 0 Posts
When I pop the p0300 code, I change the spark plugs. It depends what kind u are running. I run ngk's and change them every 3 oil changes.

I would check the spark plugs and spark plug wires.
oneonlywgs is offline  
Reply With Quote
Old Jan 19, 2009, 06:51 AM
  #5  
Evolved Member
iTrader: (25)
 
Walkingchaos's Avatar
 
Join Date: Sep 2005
Location: Boston, MA
Posts: 1,418
Thanks: 0
Thanked 0 Times in 0 Posts
its the plugs and theres no point in running anything other then 87 octane fuel in that car with those mods. Between the hotter plug and the higher octane im not suprised your having misfire issues. Toss some cheap NGK coppers in there and see if it fixes the issue.
Walkingchaos is offline  
Reply With Quote
Old Jan 19, 2009, 05:10 PM
  #6  
Newbie
Thread Starter
 
Join Date: Dec 2004
Location: Chi-Town
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Totally true (I fixed the problem) I run the higher octane gas in there out of pure superstition of "dirty" gas. i have no means of justifying that, other than I messed up injectors on two diff cars from cheap-o Citgo gas. The plugs WERE the problem, though not for what you're saying. I had a new tech at the shop install them cuz it's a new tech thing to do. Oil changes and spark plug swaps and whatnot. Simple stuff, right? I had the car at the shop today, so I took a look at the plugs. They were gapped a full .01" too wide, which put them about .011" beyond Mitsu and Pulstar spec. On top of that, one of them was cracked, and the other one on that coil was pretty fouled up. Can't say if the kid cracked it putting it in, or if it happened on its own (unlikely), but there it is. Maybe he cocked it and put a hairline fracture in it, and it cracked later, which is why everything ran fine for so long. Threw some NGJ iridium's in I had in the shop, and it runs smooth now. Thanks for the assist, sorry for cluttering up the forum. -Jx
JohnnyXmas is offline  
Reply With Quote
 
 
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
TLeid91
Evo Engine / Turbo / Drivetrain
7
Apr 4, 2016 07:43 AM
Evolcomk
EvoM Newbie / FAQs Forum
16
May 30, 2015 11:33 AM
neh2552
Evo Engine / Turbo / Drivetrain
13
Nov 17, 2010 04:42 AM
wu343
Evo Engine / Turbo / Drivetrain
22
Apr 22, 2005 11:06 AM


Thread Tools
Search this Thread
Quick Reply: PLZ HELP: P0300 , but only at high speeds. . .


Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.