r/AskAMechanic

My check engine light keeps coming on despite having just had my fuel pump replaced. When the guy who replaced my pump checked it, it was the fuel pump code again. Literally nothing is wrong with it. There are no symptoms of anything being wrong with it. It won't turn off. 2018 Subaru WRX. Not in the VIN range affected by the recall. I just want to be sure I'm not going to get stranded in the middle of nowhere on my 900-mile drive home.

Also the code was cleared out, it came back on after about 10 to 15 minutes of driving both times, and my in-car OBDII scanner is picking up the light but not the code.

I'm having the most aggravating issue with my truck and I'm hoping someone here has some insight. It has an intermittent, seemingly random misfire. It happens mostly at highway speeds, under heavy acceleration. My fuel economy is also lower than it should be/was in the past, which may or may not be related. 130k miles on the truck.

First, I did the obvious, had the spark plugs replaced (they were due anyway). Made sure to use Motorcrafts. It started misfiring again a couple days later. Eventually, it threw a CEL code, the shop read it and said it was a cylinder 3 misfire. they swapped coil packs between 3 and 1 to see if the code would move over.

Then, the truck ran perfectly for a couple weeks. Fast, slow, pedal to the metal, didn't matter, drove like it was brand new. But eventually, it started misfiring again, more and more persistently (no code though). I brought it back to the shop, they drove it around for 3 days and said they couldn't replicate the issue. They shrugged and gave the truck back to me - no work done, no cost.

After a few more weeks it finally misfired bad enough to throw another CEL code - P0300, "random misfire". I had a hellish work schedule stint and didn't have time to get to the shop, but it "self-corrected" and started driving fine on its own anyway.

A couple weeks later, it started misfiring again- same thing, more aggressively and more persistently for a few days, and it finally threw a code saying misfire on cylinder 2. Remember that the last cylinder-specific code was on 3. I brought it the mechanic immediately after the code came up this time.

It is now at the shop again and they once again are unable to replicate the issue. The tech says the spark plugs look fine, and all 6 coils tested fine as well. They've been driving it up and down the highway for 2 days trying to get it to do something and it's running perfectly fine.

I've ruled out the possibility of bad gas (filled up at many stations, no correlation). Engine air filter was just replaced 2000 miles ago. I have not done the 24E12 PCM recall but it doesn't seem like that would matter.

What I'm wondering is:

• Are there any other components that my mechanic could/should be inspecting or testing regardless of whether or not they're able to actually replicate the misfire?

• If they give up and just toss the keys back to me again, is there any DIY diagnostic stuff I could do to try and narrow down the problem?

• Would I have better luck going to a Ford dealer? I fucking hate dealerships but I know that they may have more advanced scan tools that can tell them more.

Really hoping to get to the bottom of this sooner rather than later. Thanks in advance to anyone who has relevant advice 🙏

Hi all, long time lurker.

I have a 2018 Ram 1500 5.7 that all of a sudden is giving me problems. Yesterday I drove around in the morning and parked to eat breakfast. After getting back in my truck, it wouldn't start. Just a couple clicks, then nothing. Luckily there was an auto parts store in the same parking lot. I removed my battery and took it to get tested.

They said it failed because of CCA.

Bought a new battery. Installed. Drove around all day for my work. Went out this morning, and it won't even click with the new battery. Reading 12.71 volts. Is this signs of a bad alternator? Or what else could it be?

Thanks in advance

Hello,

I have a 2010 dodge challenger for years the check engine light has been on and the tire pressure light also stays on everyday. I have a family mechanic who has done a lot of work on this car they thought it was the gas tank and have switched it twice, they then thought it was the cluster instrument he changed it for a used part and the error codes did go away for about 2 weeks but then came back again. I am wondering if anyone has come across this issue with a challenger and if it is worth looking into repairing/upgrading the cluster instrument it looks like dodge no longer creates this piece for 2010 dodge challengers so I can only find used parts. Any help is appreciated!

Hey everyone, my wife drives a 2002 Toyota RAV4. It has 114k miles and we were recently told by the shop that it needs the timing chain tensioner replaced due to a super loud rattling noise it was making. They quoted me at $2200 for the repair.

I am trying to decide if it’s worth putting $2200 into a 24 year old car vs cutting my losses, selling the car and getting something else. I also fear that they could go in to do the tensioner and find more problems with the car and it turn into a money pit.

Any advice on how to proceed?

I had my mechanic replace both my cv axles on April 5th
My passenger side cv axle popped out a month later or so around may 13 I got stuck on the road my car wouldn’t reverse or drive and make weird horrible screeching noise when I put it on park. I had my mechanic put my passenger side cv axle back in spot the next day my cv axle what making a horrible noise then that morning it seem to happen again got stuck on the road the car won’t drive or reverse makes the same noise when I put it on park not as bad as the last time. Why is my cv axle not holding up?

I was getting codes for misfires. Checked my plugs, the passenger side all had oil in them. Changed the plugs. Few days later. Same issue. Noticed the valve cover gasket was leaking. Grabbed a new gasket. Went to change it, noticed all the bolts were loose. Tried to get the cover off. Couldnt. So i thought maybe tighten them up, grab a more knowledgeable friend before i beeak anything. Replaced all the hoses and wires i disconnected. Go to start the truck, she runs. But, she wont move unless i revv high. Shifts into gear fine, no rev at idle. Idk what ive done wrong.

Got this beater work truck it has about 295k miles on the body th engine has 182k there’s some russt not a lot but i had a check engine light it should 6th cylinder misfire that’s it the truck slightly shaked before i put a new spark plug , last week i was going uphill and pushed gas a lot and it came back on , now its really slow to accelerate, when i smash the gas it’s smooth until 45 ish and then the truck kinda jolts back when it switches to 50+ and now it shakes on idle and kinda shaky when driving , the tire had a leaking valve for 3 weeks until fixed last night i’ve had tho truck for about a month it hasn’t broken down 😅 or had any problem besides the one stated , can anyone give me suggestions please ?

08 legacy 170k miles non-turb 2L eating oil but not leaking, currently using 5w-30 in it would using a thicker oil slow oil useage or is it more likely to cause issues? And no im not willing to rebuild it.