Solving Automotive Performance Issues
Identify the Problem
Vehicle performance problems can result from anything from engine performance issues to problems with the driveline. The first step with any performance problem is to try to isolate the source of the problem. With a little time and some detective work, you should be able to identify the problem and begin your repair.
The Basics
Before we get too deep into this complex topic, it’s worth mentioning that you should always check the basics when you have a performance problem with your vehicle. You’d be amazed at how just doing a tune-up on an engine can cure a whole host of problems. In fact, I’d insist that you check these things prior to your diagnosis. Check your spark plugs, air filter, fuel filter (if your vehicle has one), distributor cap and rotor (if equipped), and the oil level. Keep It Simple Stupid, the rule of K.I.S.S., is something to live by when it comes to performance diagnosis.
Many of you come to me with complex assumptions that some sensor somewhere is causing all your problems. This is the way of the dark side; avoid it. Follow the evidence, and you will find the truth. Assumptions waste your time and money. Why not start by checking the oil? On more than one occasion, an engine has had a loss of power and the cause was low or no oil in the crankcase. No kidding. Remember the movie Sling Blade? The main character, who is a lawnmower mechanic, walks over to a couple of guys working on a mower who are scratching their heads trying to figure out why a mower won’t start. The main character removes the gas cap and says, “It’s got no gas in it.” Sure, laugh now, but the truth is you might be guilty of this very thing. I know I’ve been guilty of it a time or two.
Check the oil, check to see if it’s got gas in it, check the tune-up items, look for simple things. Don’t waste your time looking for complex solutions. Just because you view a computer-controlled engine as a complex machine, it doesn’t mean it is. It still needs oil, it still needs gas, it needs air to breathe and a good set of spark plugs, and it needs to be in time and mechanically sound. All those computer-controlled components are there to make sure it performs well under a variety of conditions; the engine still works the same as it did a hundred years ago. Remember, K.I.S.S. and you might just save yourself a bunch of time and money.
Pulling Codes
One of the easiest things to check for are any indicator lights that might be on the instrument cluster. If you have a check engine light (CEL/MIL) or other warning light, this is the best place to begin your search for the cause of a performance problem. In fact, even if you don’t have a check engine light on, pull the codes. You may find you have codes stored with no indicator on the dash. It wouldn’t be the first time this has happened. Sometimes the bulb burns out, or someone has disabled it for whatever reason. It’s for that reason you should check for codes first thing even if you don’t have a CEL. These lights are often associated with a particular code that could indicate a system fault. These codes are created and stored in the PCM (Powertrain Control Module) to aid in the diagnosis of a particular fault. Codes can represent problems with the engine or its management systems, the transmission and its systems, the ABS (Antilock Brake System) or TCS (Traction Control Systems); even a problem with the ABS or braking system can cause a performance problem.
Sometimes when a given fault is registered by the computer, it puts your vehicle into what is called limp-in mode. This limp-in mode is designed to preserve the engine and transmission during a particular fault. In the process of putting the vehicle into limp-in mode, it limits certain functions, such as the maximum RPM your engine will rev or the timing of the transmission shifts. This is a measure of self preservation to the drive train; it also gives you the ability to make it to the nearest service center to have things checked out before you damage something.
So for starters, pull any codes you might have. As stated, it’s not a bad idea to check for codes even if you don’t have any dash warning lights on; sometimes the lights have burned out or been disabled. If this is the case, the codes will still be stored in memory, but you won’t see the warning lights on the dash to indicate a fault has been detected. Here’s a video on pulling these codes.
Pulling Codes, Pre OBDII
On vehicles older than 1996, you might need to follow a different procedure. Every manufacturer before that time had their own way of storing and presenting fault codes. The upside is that these vehicles often don’t require that you hook up a scanner to retrieve codes. Check your service manual for the procedure for your vehicle. You might find this video on how to pull codes from a Honda or Acura without a scanner helpful. Consult the service manual for specifics on the vehicle you’re working on.
Video Title: Solving Automotive Idle Problems – EricTheCarGuy Video Description: In this Article, Solving Automotive Performance Issues, Eric looks at what can be the cause of Solving Automotive Performance Issues with your vehicle .Thumbnail: http://www.ericthecarguy.com/images/faq_buttons/Large_FAQ_Images/Performance-and-Driveability-icon-large.png
13 thoughts on “Solving Automotive Performance Issues”
Giovanni Alfonso
November 3, 2022 at 1:19 pm
Good afternoon Eric , I have a 2007 ford expedition EL Eddie Baur. I have codes P0172,P0175. I have spent a lot of money changing parts. I have changes everything that I can think of when coming to a car running rich. And the car is still running rich i don’t know what else to do. I have changes o2 sensors all of them, fuel filter, fuel pump, spark plugs, injectors, purge valve, MAF sensor ECT sensor both Catalytic converters. Can you please help me. Oh and also took my computer to get looked at and they told me is fine.
Iliya
July 18, 2022 at 6:57 am
Love your videos Eric 🙂 I have a Suzuki alto 2011, and in the last
3 years ,sometime, randomly, especially (but not only) in the first 5 -10 minutes of its operation, the viechle stalls when I press the clutch pedal during ride. I start the engine immediately back on without any problem. It might occur
1 to 4 times during those 10 minutes, and then mostly it keeps driving without any problem after that (it might not stall at all in the first place). A side note is that it happens more often during winter. The OBD scanner reveals nothing and no other obvious sign appears (a very rare ESP light might appears but I don’t think it relates to the mentioned problem), but I suspect that its about a dirty throttle body, and maybe a simple clean up will hopefully solve the problem. But before I do that (its a little complicated in my car) I would like to hear your thoughts about it… again, I really appreciate your work and hope to hear your answer or somebody’s else in the audience 🙂
ישראל נוישטט
August 3, 2022 at 4:51 pm
hi how did you rezolve the cars problem
I have it too in my suzuki car
Ralph Bowes
February 21, 2022 at 3:37 pm
Hi Eric,
I love your channel. I have a 2007 Ford F150 with a 5.4l. It will barely move. Max speed maybe 5 mph. It runs good in park and you can rev the engine but as soon as you put it in gear you have no power. The rpms do not go up past 1500. I ran codes and I got p0300, p0305, p0306, p0308, p0316 and p0420. Could you please give me an idea about what is going on or possibly where to start? Thank you have a great day!
Northshore
March 31, 2022 at 5:02 pm
Plugged cat
Eli
January 24, 2022 at 5:33 am
Hi Eric,
I own a 2003 Acura CL Type-S with a 6-speed manual(195k miles). I have a a random misfire on an assortment of cylinders for some time now. I have replaced/serviced the following: the spark plugs, coils, valve adjustment, valve cover gaskets, plenum gasket, EGR port cleaning, EGR Gasket replacement, and throttle body gasket, and checked for vacuum leaks. I was wondering where the next step would be to try to resolve this issue. There is a little electrical whine when I accelerate (maybe bad ground(?)) and I was curious if you think that could trigger that many misfires. Any direction or advice is much appreciated. Thank you and have a good day
Eddie
April 25, 2022 at 11:47 pm
Hi Eric I in need if help if u would please contact me back i have a 98 honda civic runs good motor warms uo the. It hesitates an bearly moves let it set an cool down works fine
Gabe
March 31, 2021 at 5:29 am
Hi Eric. I have a 2011 Dodge Caliber Mainstreet. I have code p0301. It seems that my misfire is turning out to be a serious issue and I need some insight. I’m currently checking all the small things that I know of before replacing parts for cylinder 1. All spark plugs and coils are good. Fuel injector is not clogged, it is working properly and ohms match the manual. I looked at the intake valves through fuel injector port, they are clean. I do have carbon build up in the combustion chamber. Compression test performed on all cylinders shows high readings of 200 to 219 psi (Are high readings due to carbon build up?). Another thing I read is that sticky valves or bent valves could be an issue and I could check doing a paper test. The exhaust is making the paper pulsate rapidly and is being sucked into the pipe. Also I took the oil cap off while the engine was running and there is a loud chopper like sound with a lot of air being forced out of the oil port. I couldn’t find anything that explained what that means. I did find articles talking about blowby gasses but all said I should see white smoke. There is no white smoke coming out. Is my issue still classified as blowby gasses or do I have a different issue?
Jessica Gregory
November 20, 2020 at 3:59 pm
Dear Eric the car guy, I have a 2004 Toyota camry 4 cylinder so my spark plug blew out of my engine it was replaced 4 months prior to these. Should I try to fix it or do you think I should get a new engine? If thats the case ill sell it can’t afford a new engine.
Roberto
March 30, 2022 at 7:57 pm
Erick i have a 2008 Honda Accord that won’t go past 3000 rpms. Sometimes when cold it will trow misfire codes p301,!p302 and p302 or p0300 i eease them and codes won’t come back.
Jared
October 18, 2020 at 11:51 am
Hello @EricTheCarGuy,I am Jared from Kenya,I changed the Engine for my Subaru Lagacy,from then I got a real big problem…whenever I step on the gas,the car strain and just goes off,but as I disconnect the MAP sensor it pick to it’s maximum power.What might be the problem?.
Kelvin Exum
June 10, 2020 at 10:14 am
I have a 98 Lexus gs400. On the most part, my car runs quiet and smooth. Other times, it will have a bad idle. So bad at times that the check light will flash but later stay steady. I have gotten it checked to find out it is misfiring on one side of the engine.
Jim srack
July 16, 2020 at 5:22 pm
Hello Eric, your the Man. Ok here’s the situation Honda Element 2003 replaced Vetec solenoid, screen was clean in old part. Thought it was resolved, however the surge came back even at a lesser rpm before the surge than previously. What I don’t get is if the screen is clean whats causing the surging. Thank you in advance for your response