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Ok, here is my issue. When I first start up my Acura the engine has a hiccup while in idle. However, if I put it in drive and start to drive without stopping the engine will run fine. If, however, I have to stop after a short distance the engine will start to hiccup and then the VTM engine light will come on. I can then, stop the car and restart and the VTM light will go off. Now for the strange part. If I drive long enough without the VTM coming on the car will warm up and the engine will run smoothly without any issues at all. I can then start and stop the vehicle and this issue does not happen again. It only happens when the car has been sitting for a day or the engine has completely cooled down. I pulled two codes from my reader they are as follows. P0172 - System Too Rich Bank 1 and P0336 Crankshaft position sensor A Circuit Range / Performance. I recently replaced my Crankshaft position sensor and this issue did not resolve itself. I have posted a video of what the vehicle is doing to show you. This issue has been going on for about 6 months, but it wasn't too bad for about 5 months. I would simply start the car and some times the engine was fine and would run without issue. Then on occasion, this started to happen on startup. I would, however, before the car had a chance to register the VTM light I would drive it and it would be fine. I would like anyone's opinion on what this might be. I have changed my own timing belts twice on the life of the vehicle and I know it's not a timing issue.

I would like to get this fixed for now the vehicle will stall while running. Last night I drove it and had to start and stop it like 7 times while driving to Home Depot. But, when I got what I needed from Home Depot I started it up and it ran and idled fine. No issues driving it back, no stutter or hiccup.

I don't want to take it to the steeler if I don't have to. Do you think I have a defective Crankshaft sensor? Or do you think something like the mass airflow sensor might be an issue?

Anyway, thanks in advance for anyone who thinks they might know what the issue might be and how to fix it.


 

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With the crankshaft sensor error code showing up, I'd be really tempted to swap out the sensor, or at least take a long, hard look at the associated wiring (a bad connector or funky wire could be causing the problem). The biggest problem with an issue like this one is trying to troubleshoot it since it's likely to be "working fine" at any given time. It sure wouldn't be the first time a new part was flaky (especially if it was a real off-brand part - there are some truly awful parts being sold online these days).
 

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If the P0172 is not because of a bad sensor, it’s probably the fuel pump. The symptoms you describe that occur when the engine is cold and have worsened over time could be due to the fuel pressure not being sufficient if it’s lost over time as the X sits due to the check valve in the fuel pump not holding pressure. FWIW, my thinking is your CKP is getting fooled by the missing or flat spotting.

My suggestion would be to have the fuel pressure checked at idle and at higher 2Kish rpm. You can get loaner tools from Autozone or O’Reillys but working on the fuel system is dangerous to people, the X. and property. I’m a DIYer, not a pro but have a post on this forum from my fuel pressure and pump change experience. No promises it will fix your issue but might help on what’s involved.

One thing you can try is to put the ignition key to position II 3-4 times and wait 2 secs betwen intervals before starting the X. In the 2 sec interval you should hear a hum which is the fuel pump charging the line.

Whatever it is, you should get it fixed. Continual missing or flat spotting can cause engine damage - skip a tooth on the timing belt, blow a head gasket.

Good luck!
 

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P0172 is a Bank 1 Rich code. Means either too much fuel or not enough air. Really, only too much fuel. Seen it before where both banks are running rich, but only one pops the code. Two biggest culprits are valves out of adjustment (fits with your mileage) or blown head gaskets. Here's a little tip: start the engine from cold, go back to the tailpipes and feel if the exhaust is "puffing" or smooth. If you feel on/off puttering against your hand...get ready to do some valve adjustments.
 
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