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Car sort of "jumps" back and fourth while driving uphill

Not sure if this is called “sputtering” or something else. But essentially today all of the sudden my car would sort of jump ahead, as if I when revving it back and fourth on the pedal aggressively. Not sure what could have caused this. Today was an essentially cold day so that may have something to do with it. Also my car overheats so I have to put anti-freeze in it most days. For the last few days I’ve been just using plain water, could this be the culprit? Please CarTalk community I need help. Why is my car jerking around like this?

Thank you

If you have to add coolant every day and the car overheats you may have a blown head gasket which is causing coolant to enter a cylinder which in turn is causing a misfire.

It’s been like this for about a year and a half I just haven’t had the money to fix the head gasket. I am thinking it is something else because this jerking back and fourth motion just started today. Thank you for you input though!

Can you see coolant leaking / dripping on the ground? Is there white smoke coming out the tailpipe?

What kind of car, eng and year? Have you replaced the radiator cap if it has one? How about the thermostat? Have you checked the radiator and hoses for leaks? Do not use water in freezing temps. It will freeze expand and crack the block, radiator or at least blow the freeze plugs.

I had a whole discussion on this issue a few months ago on my post “Mysterious overheating honda” all the information about it is there. No white smoke, no telltale signs of a blown head-gasket other than it overheating. And I’ve had the tests done. The antifreeze seems to leak out when I drive, so it overheats and drips out or evaporates? however that works. The group here seems to agree it’s some sort of pinhole leak in the head gasket causing the overheating.

@knfenimore‌ yes radiator cap, thermostat and horses have all been checked and replaced. Please refer to the post “Mysterious overheating honda” It’s been the biggest pain in the rear for me. I have to commute back and fourth to school 120miles altogether, so you can imagine the stress.

At this point, due to the new symptom of “sputtering” I would pull the spark plugs and visually compare them.

What should I be keeping an out for?

Thank you

“What should I be keeping an [eye] out for?”

A dark plug insulator means it’s misfiring. Also, eroded electrodes

Also, look for one that looks different than the others.

Maybe check the gap between too? I heard that means it’s gone bad if it’s beyond .040-.045 thousandths of an inch.

Oddly enough it didn’t do that today. Maybe a weather related issue?

If the gap is to wide it will cause rough running. If it does it when raining wire are bad or coil may be cracked. Here is condition chart.

Now the “check engine light” came on. I am thinking it needs new spark plugs because it’s hesitating on acceleration.

Get the code read at the local parts store and report back. Code should be a letter followed by 4 numbers. (example P0402)

If you have no signs of a blown head gasket and believe that it MIGHT NOT be blown…WHAT ON EARTH are you waiting for ??? This coolant “Issue” will get NIGHTMARISHLY EXPENSIVE when you finally DO blow or melt that head gasket because of NOT repairing this coolant leak. WOW…I need to be careful what I say here… ANYWAY…FIX THE COOLANT LEAK… BEFORE you either snap the Waterpump shaft for lack of any lubricant in the coolant by using water…Destroy the Head gasket…Warp the cylinder head…or basically RUIN your vehicle… I will NEVER understand people and their relationships with their vehicles. Being a self taught mechanic myself it worrys me when I hear stories like this. PLEASE help your vehicle out and find the leak and fix the issue…BEFORE it costs you 10X what it normally would to repair

Blackbird

Honda Blackbird I WOULD GLADY HAVE IT FIXED…It’s not like I think to myself “Hey I want my car to run like crap so YEP I’ll just treat it like crap do-do-do-do-doo” no I’d like to have my car working in tip top shape BUT here’s the problem it’s expensive as all hell for me to fix I am a broke college student that can’t afford to dish out $800+ more to fix the head-gasket. I know it’s a bad head-gasket numerous mechanics have come to this same conclusion, there are too many signs which point to it. But I am not loaded.

Update: Got a code reading today, turns out I have a bad ignition coil. 40$ it sounds like. So that’s a relief.

Replace the plugs while you are in there. Great to hear it’s only a coil, but bad plug can give you a bad coil code.