Q: When I accelerate, my car hesitates, the rpms bounce, and sometimes i have a missfire flashing CEL

asked by on October 11, 2016

My car is hesitating upon acceleration, no matter how fast im going if I give it too much accelerator it bogs down. Also when I accelerate sometimes the rpms wont go up, they will actually slowly drift down, then when I release the accelerator pedal, they jump up quick then fall back down. I have already changed the ignition coils. The spark plugs have maybe 10000 miles on them, theyre ac delco iridium plugs, it has taylor spiro cables on it. I have completely and thoroughly cleaned the throttle body, the EGR valve and passage ways, unplugged any electrical connector I could find and sprayed it with electrical connector cleaner. I have order the accelerator pedal sensor as this is what the car seems to need but Im unsure because it never throws a code for that specifically, it just says bad egr valve, bad correlation between Map sensor/maf sensor/and throttle. Also says running lean on bank one. If you need more info just ask.

My car has 183000 miles.
My car has an automatic transmission.

Hello and thank you for your question. With having your engine with bank 1 being lean (lack of fuel), the symptoms are showing that there is a problem with fuel delivery or excessive heat. If the EGR valve was to be stuck open, the engine will get more burnt fuel into the cylinders and cause them to heat up making the computer back off the fuel until needed.

The MAF sensor tells the computer how much air is coming in the engine. The MAP sensor tells the computer how much pressure is on the manifold. The throttle position sensor tells the computer where the throttle plate is located at.

If you are getting a code for bad connection between all of these sensors, then there is a bad ground connection or the harness to the vehicle is broken somewhere. The ground to the sensors are in the computer and the throttle pedal. So if the ground is the problem, then you would need to replace the computer or throttle pedal or both. Check all of the harness plugs to all of the sensors and use a digital volt meter to check for power to all the sensor harness connections using a paperclip. Then check all of the ground circuits with resistance. If you have some resistance but not a lot, then the circuits are okay. If you have no resistance, then the ground circuits are broken somewhere between the harness plugs and the computer or pedal. I would recommend having a professional diagnose the hesitation issue and move forward with appropriate repairs.

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