Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

P0172 p0300


Our 2004 Saturn Vue with the 2.2L 5 speed manual is throwing a P0172 and a P0300. Car starts every time and drives fine. Has no problem on the freeway.

However, it has this “rythmic and constant” shake on idle that starts under 1000 rpms. It is most noticeable at 700+ rpm. You can feel the whole car shaking and you can see and hear it on the exhaust tailpipe too. I can attach a video if you guys like.

Sometimes after driving a while the car idles at 1000 rpm… sometimes it idles at 700 rpm. I don’t see the tach needle jumping around.

LTFT numbers are -8 to -14 depending on load. I took it to a shop for diagnosis. They told me that it was a problem with the throttle body.

I replaced this part myself but nothing changed. They wanted $100 for throttle body calibration but I was told by an ex Saturn dealer tech that I could do this myself without a scan tool by following a GM throttle body relearn procedure…

Vehicle already has a new coilpack, ICM and new plugs.

I have attached the shop observations here.

I tried to get second opinions from other shops but because of the Coronavirus situation most places are closed. Any help is appreciated.

Thank you.

Well I guess nobody knows.

Pretty impatient aren’t you? You only posted this 9 hours ago.

So did you DO the throttle body re-learn?

Consistent with a rich fuel condition. Cylinder #3 is a little weak but the immediate problem is the rich fuel condition. I’d suggest you might have a MAP sensor problem. If the shop tested the vacuum with a real gauge and then compared it to the MAP sensor reading, that may have identified the problem if they did not match but there is no comment about that in the report.

If this is the “second opinion” you were looking for, I can only suggest you get that 2nd opinion from another shop by paying them their diagnostic fee to do what the previous mechanic did. But I doubt you’d want to do that because you didn’t want to pay the first shop to fix it.

I am posting this to help others with the 2.2 ECOTEC. The MAP sensor was good. The EVAP purge too.

Because most shops were closed I decided to buckle up and find the problem myself. I ruled out everything.

In the end the timing was off. Found the plastic chain guide broke. Lucky for me the valves are okay. Thermostat was bad too. The plastic guides breaking is a common problem in the 2.2 Ecotecs it seems. Everything is good now after replacing the chain with a Cloyes kit.


Excellent work. So many people just skip right over checking the engines base mechanical timing…

Can tell you how many issues I’ve resolved over the decades by starting at Good Ole Square One… timing verification… everything hinges upon it…

The rich condition was caused by the delayed (late) fuel and ignition events… Any seasoned mechanic should have recognized the symptoms of the base timing being off… but that is a story for another thread maybe.

Again nice work and thank you for updating us