Chris a Jackson

So my 2007 equinox had several problems after 1 year of purchasing it. It starting over heating. Started with the obvious which was the thermostat not it of course. After 3 breakdowns and several trips to mechanic finally had replace the head gasket. Great now I'm all good or so i thought. No longer having the over heating issue. Now it's throwing stabilitrak code and also once i get to 40 it jerks. I let my foot off the gas and I'm fine until i hit 60 then it jerks and keeps jerking until i let off. I have decided to not take it on the highway since i don't want to be stuck and can't take it to speed anyway. I have taken it to get checked out and the only thing that comes up is egr valve. I have to say after reading what everyone else is saying about the equinox i feel i am just left hanging without an answer but if anyone has one please let me know. I absolutely love this vehicle but starting to think it's time to get rid of my equinox.

ruley73

A bad EGR valve is actually a common cause of Stabilitrak being disabled on the 2005-2009 Equinox (3.4L). This may seem odd if you've never heard this before, but I can assure you it's absolutely true. We've owned our 2007 Equinox since 2008. It's on it's third EGR valve.

Head gaskets usually don't fail by themselves on these engines. Make sure both radiator cooling fans run like they should. A common failure point is the connector going to each fan motor. The connection becomes weak with time which increases resistance and eventually melts the plug.

Can you elaborate on what the jerking is? How many miles does it have? Have you ever changed the spark plugs & wires? With good care, these vehicles are very reliable and can run a long time.

Chris a Jackson

I have no clue as to what the jerking is. My equinox has 130,000 miles on it. It gets a tune up once a year which includes spark plugs and wires and is well taken care of. I never miss a oil change and runs fine as long as i don't take it over 40. Once it gets to 40 it jerks like a hesitation i guess. I don't know how else to explain it. Again i loved this vehicle and take very good care of it but i don't understand the issues it is having. There is no issue with it over heating anymore since i got the head gaskets fixed. But the jerk has me up at arms.. I reach 40 it jerks i let off the gas it's fine.

ruley73

Does the check engine light come on or blink when it jerks? I hope you're not changing spark plugs and wires with your annual tune-up because that would be extreme overkill. I might even argue that an annual tune-up isn't necessary to begin with. There isn't much that requires regular service at that rate on these vehicles besides oil changes and air filters. If you haven't already replaced the plugs & wires, I would definitely start there. I only recommend the AC Delco Iridium plugs. Our Equinox has 200k miles on it and I've only changed the plugs and wires once at 93k miles. I think the plugs could've easily went at least another 20k miles or so because they still looked good at that time, but I already had the parts so I replaced them anyways. It's about due for it again, but it still runs good. I don't plan to change the plugs & wires again until I start seeing misfire codes because it's now a secondary vehicle and I'm not sure how much longer we'll have it.

An educated guess for the cause of the jerking would be weak fuel pressure, but I'd think you'd feel jerking/hesitation when accelerating hard from a stop if that were the case. Did it run fine at any point after replacing the head gasket?

Chris a Jackson

Yes it ran great after replacing head gasket for about 2 years. There are no misfire codes. Yes i do get the spark plugs and wires changed once a year. This may be over kill to you but i feel it is necessary. I don't have the jerking until i reach 40 and above. I am not hard on my vehicle because it is an older vehicle. Yes the check engine light is on which is why i had it checked and only got the egr valve code. Of its weak fuel pressure how would i fix that and why wouldn't it show a code for that?

Chris a Jackson

Yes it ran great after replacing head gasket for about 2 years. There are no misfire codes. Yes i do get the spark plugs and wires changed once a year. This may be over kill to you but i feel it is necessary. I don't have the jerking until i reach 40 and above. I am not hard on my vehicle because it is an older vehicle. Yes the check engine light is on which is why i had it checked and only got the egr valve code. Of its weak fuel pressure how would i fix that and why wouldn't it show a code for that?

ruley73

We simply need more context than "it jerks."

Have you had any recent work done that the issue seemed to start after (like a tune up)?
Does engine RPM seem to be limited?
Does it start doing it at 40 MPH and get worse as speed increases or does it start suddenly and behave the same no matter how fast you go above 40 MPH?
Does it act the same way regardless of how much throttle is applied when exceeding 40 mph?
Does it pull to one side?
Do you feel it in the steering wheel?
Does it stop immediately when you apply the brakes or just let of the throttle?
Does it seem to be more of a chassis/suspension issue or an engine/trans issue?
Has the chassis/suspension been inspected recently? Wheel alignment checked? Is the tire tread wearing evenly?

There could be a number of things wrong as old as it is. It could just be the wheel alignment (front or rear), but bad bushings or worn parts like tie rods/ball joints could cause the problem. If you've never changed the transmission fluid, that would be a good idea too.

To answer your question, most vehicles with a gasoline engine (including the 2005-2009 Equinox 3.4L) don't have an onboard sensor that directly monitors fuel system pressure, so there's no applicable code that can be triggered for fuel pressure alone. Sometimes, but not always low fuel pressure causes other issues such as misfires that would cause a check engine light. Fuel pressure sensors are starting to be used more often on newer vehicles though. Our other vehicle (2018 Chrysler Pacifica) has one.

What are the exact code numbers you're getting? I would recommend replacing the EGR valve, but admit it's probably not the cause of the jerking. Before buying the new EGR valve, inspect the tube the goes between the EGR valve and the exhaust manifold. I had to replace this the last time I replaced the EGR valve on ours. It cracked and caused an audible exhaust leak.