Inconsistent studdering

[anishemaya]

2012 Expy EL 160k miles....so here is the my problem. There are times when as I accelerate the truck studders & seems like it's changing gears roughly...then a couple of times it studders with the check engine light blinking & the A/c starts blowing hot air... again nothing consistent. I was told it was probably a coil pack? ( I think that's what he said not sure) I drive over 3k miles a month not sure if that is relevant. BTW the check engine light comes on depending on the fuel level. I have taken it to the auto parts store to read the codes. They say it's O2 sensor. Thoughts? TIA!

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[gixer2000]

Blinking service engine light is a misfire. I would start with plugs and move the coil from the misfire cylinder to another to see if the mis follows

 

[1955moose]

What exactly are the codes that they came up with? Are you doing the work yourself? Or are you arming yourself before taking it to your mechanic?

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[anishemaya]

I don't know specifically what the codes we're. The guy just said it was O2 sensor bank. I can take the truck by there again and find out. Unless it's as simple as putting gas in the tank, I am looking to not get ***** by a mechanic.

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[1955moose]

The 02 sensor code can actually be a lot of things, believe it or not rarely the 02 sensor itself. Your mechanic will most likely run his/her own diagnostic, and check fuel trim during different parts of the throttle range. Anytime a misfire occurs like a bad coil, or spark plug misfire, it will affect the shifting on a automatic transmission. Is your AC blowing cold the rest of the time? Is it warm air just during misfire/ check engine light flash? That part is kinda strange. Might be a whole different issue. Hope that helps a little.

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[Ps4acc88]

Having the same issue, except my truck wont register a code. I got the blinking check engine light also, but nothing comes up during a scan.

 

[gixer2000]

Having the same issue, except my truck wont register a code. I got the blinking check engine light also, but nothing comes up during a scan.

A blinking SES won't throw a code until it sees a set about of misfires. You need a scanner with mode 6 to show the misfire before a code is set

 

[1955moose]

If your getting a misfire that won't trip the light or register on the scanner is weird. Sometimes you've got to hold it at that misfire point to set a code. Fuel delivery like a failing pump, or a catalytic convertor are items that don't trip codes. That's why we always recommend fuel pressure readings. And backpressure at the front 02 port. Generally a blinking check engine light is a serious misfire that shouldn't be ignored. Be sure your data port is powered OK. Try clearing all codes and go from there. You might try a different scanner, whether yours, or have one of the freebie tests done. Cops are usually the biggest offender on the blinking light.

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[Jeremy W]

I had a similar issue and swapped all of my coil packs out. Cost me $200 to get them from Autozone and about 30 minutes to swap them all out, only one of them gave me trouble getting it in.

My studder was only between 40-50mph, felt like the transmission was searching for a gear. Only had the engine light blink once or twice. Here was the YT video I found for a F150, but it's applicable to the Expy as well...