Car sputtering, engine light flashing
- Thread starter CB88
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On my 1995 Neon I got a flashing engine light and then a sputtering engine. Turned out a coolant temperature sensor went and it was reading full cold, so the ECU was thinking it was -40C and going full rich. New sensor and it was fine.
The point is that it needs some real diagnosis before buying parts.
The point is that it needs some real diagnosis before buying parts.
The intake/induction side should've been smoked to find any air leaks that would cause high positive fuel trim %. If no smoke is visible then check fuel delivery.
What brand of injectors has it been replaced with? I threw a set of GB Reman injectors on an 08 Corolla a year ago which initially solved the lean issue. Now it has become problematic where it was throwing a p0304 code and high positive fuel trims (but not high enough to throw a p0171.)
What brand of injectors has it been replaced with? I threw a set of GB Reman injectors on an 08 Corolla a year ago which initially solved the lean issue. Now it has become problematic where it was throwing a p0304 code and high positive fuel trims (but not high enough to throw a p0171.)
LA should have at least a few woman-friendly repair shops. Ask some friends for their experiences. If the car is drivable, take it to an auto parts store and get the codes read so you have more info.
This is how I ended up at this shop. I asked a friend for a recommendation! The car is not drivable, I have to tow it to the next shop.
Thank you. Not all shops are able to do a smoke test. I used to take it to a place I trusted when I lived 10 miles away, but when the 171 code appeared, I asked them to do a smoke test, and they said they did not have the right equipment to do so. At the time, they checked the car and told me I could keep on driving it.
Thank you. Makes sense.
My sister's Toyota Matrix (same engine) has the same code but no misfire (had a misfire also previously and replacing the ECM fixed that and a separate ignition coil circuit code). Then it had a pending MAF code, new Denso MAF helped the issue but the p0171 kept coming back and I confirmed a leak at the intake gasket. Seems like the previous owner sold it with 3 separate issues. None of which were ignition coils.
Could be just the spark plug wires. My GEO prizm would have the #4 plug wire go bad about every 50k miles or so. Very similar symptoms
ah...does not have spark plug wires
Thank you for the tip.
It's nearly a requisite tool for a shop. I understand DIY guys not having one but this really is a core diag tool.
Cheap ones are all over Amazon, but a shop should have at least something like the Icon (safe for EVAP) and they're still only about $500, which shouldn't be a big hit in the face of potential ROI and time saved diagnosing
2 known issues when that code appears on a 9th gen Corolla:
1) Dirty/defective MAF sensor.
2) Leaking Intake manifold gasket.
Both of these issues are common to the 1ZZFE. Try cleaning the MAF sensor first, reset the CEL, and see if it reappears. If and when you replace the Intake manifold gasket, ensure you get the newly revised orange silicone gasket, not the black rubber one.
(Ask me how I know)
Edit: So after re-reading your initial thread, I do see that the MAF was replaced.
My money is on the Intake manifold gasket. GL.
1) Dirty/defective MAF sensor.
2) Leaking Intake manifold gasket.
Both of these issues are common to the 1ZZFE. Try cleaning the MAF sensor first, reset the CEL, and see if it reappears. If and when you replace the Intake manifold gasket, ensure you get the newly revised orange silicone gasket, not the black rubber one.
(Ask me how I know)
Edit: So after re-reading your initial thread, I do see that the MAF was replaced.
My money is on the Intake manifold gasket. GL.
Last edited:
Thank you.
I've heard if you spray (unlit) propane in the vicinity of a vacuum leak, it will raise the idle substantially (& fuel trim will change). I have 2 Matrixes & my Corolla in the extended family, I've not had a bad intake manifold gasket yet (& the Corolla has 176K on it now)! Let us know what they find on it, it might help in the future!
Thanks
Update: I had the car towed to a mechanic who had previously done work on my car and he was about 10 miles away, but it was worth it, as he replaced a coil and put a new battery on and the car is now working. The engine light came back on, but it's been on and off for a couple of years now, and I will read through all the replies again and see what else I can do about it, probably starting with trying to determine if there is an air leak somewhere. And i should probably have them check if the code PO 171 is still there.
At least I have transportation for now. Thank you every one for your help.
At least I have transportation for now. Thank you every one for your help.
The P0171 is indicating a lean condition and should be dealt with. What were your instructions to this new mechanic when you dropped it off? Only to get it running?
One good way to determine if a lean condition is caused by a vacuum leak is to monitor fuel trims and rev the engine to 2,000 rpms or more and see if the fuel trims come down closer to normal. Unfortunately, a lot of mechanics seem to be parts changers instead of trying to diagnose anything. You need a shop that is good at diagnosing and drivability problems. Maybe this new shop is depending on what you told them to fix.
Thank you for the tips. I asked them to find out what was wrong, and told them about the PO 171 code. I will go speak with them in the next few days and ask them about checking a vacuum leak. Actually when I picked up the car, there was no engine light. It came back after driving it for a day.
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