My husband has a 2002 Frontier, which has a problem of not wanting to go over 65 and sometimes it won't go over 45 mph. When we push the gas, it doesn't move. When we let it off, it goes. Sounds like an EGR problem but no EGR.
On those, I can just about guarantee you that it's a clogged up catalytic converter. It was a design flaw on those vehicles. Have the catalytic converter pressure tested. When they clog up, the gas can't escape the car so it can only go so fast as the engine can't spin any faster because it can't pump any more gas out. There is no place for it to go. You will need to have it pressure tested to see if it's the catalytic converter.
Also consider that it is a V6. Those have two catalytic converters and they cost a whole bunch of money but they often need replacement. If you need help with this, a technician from YourMechanic can inspect your acceleration issue and replace your catalytic converter for you if necessary.
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