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Ask Jerry Your Own Question
Jerry, Master Mechanic
Category: Dodge
Satisfied Customers: 1754
Experience:  ASE Master tech, 30 years exp. troubleshooter, driveability tech
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Have new PCM, block, injectors and plugs. Runs great but

Customer Question

Have new PCM, long block, injectors and plugs. Runs great but stumbles at higher speeds when you get on it.
JA: Sometimes things that you think will be really complicated end up being easy to fix with Dodge. The Dodge Mechanic I'm going to connect you with knows all the tricks and shortcuts. Tell me a bit more about what's going on so he can help you best.
Customer: At higher rpm, it drops off when excelerator. It will catch up, then stumble, catch up then stumble again and again.
JA: Are you hoping to fix this yourself?
Customer: If I can?
JA: Is there anything else the Dodge Mechanic should be aware of about your Dodge?
Customer: Since the new PCM, the speedometer and odometer are fast. At about 65-70 speed reads 100.
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Dodge Mechanic about your situation and then connect you two.
Submitted: 1 year ago.
Category: Dodge
Expert:  Reggie Whiddon replied 1 year ago.

You say the speedometer is reading fast, let me ask you have you noticed this problem occuring at a certain speed,? I am asking because if it runs great otherwise the pcm has a built in cut off at certiain speed some cars its a 100 others 110 120 and so on. If your speedometer is that far off you may only be doing 85 and the governor in the pcm will cut power to injectors at the cutoff speed but when you let off gas and decrease your speed it cuts back on when this happens it feels like a skip almost or it cutting out. Why is the speedo off has there been a gear or tire size change