2005 Nissan Titan Chugs on Acceleration

That was the mechanics first thought too but if it has bad fuel pressure (high or low), wouldn't that throw a code?

It does sound like it May not be getting enough fuel. Somebody with a fuel gauge should be able to drive it (with fuel gauge connected) and see if there is continuous good fuel pressure. Another possible cause of low fuel delivery is a faulty/dirty mass air flow sensor. if it is dirty, you may be able to clean it and notice an improvement.

I have been experiencing this issue. extreme loss of power from standstill say from a red light. Or driving 65-70 mph and suddenly feels like someone has hit me from the rear, then gradual loss of speed and power. if I stop and turn the engine off for a few seconds, all is goo for several miles then might do the same from a standstill again. same thing, turn off engine and it may clear for a hundred miles. It has stopped for over two weeks now and running normal, very good acceleration and runs normal. the only thing I have changed is the ignition key. The old key would need to be turned to start several times sometimes because all I could hear was a click. That has gone away also. I have hade similar issues in the past with bad acceleration , bad coil, MAF, catalytics , fuel issues, ALL of them set a service engine code because they affect emissions. A bad battery or corroded connections will affect performance. The key question mystifies me unless there is a loss of programming or a program malfunction in the old key.

Sounds to me it maybe a clogged fuel filter or weak fuel pump. Check the fuel pressure see if it’s getting right pressure

Mine is doing the same thing. I don’t know much about vehicles but I have the exact same truck and it is chugging when I accelerate quick. From what I read, it could be in limp mode because it seems like it doesn’t want to reach a high amount of rpms when it’s in drive, but also I don’t know what the dealership did before they handed me the keys but my oil pressure is all the way up. I want to be positive on what the problem is because I have 2 days to return it.

Mine won't start right it stalls out when out in gear and it will stall cuz it falls under 500 rpms throws crankshaft position sensor replaced it but keeps coming up

2004 278,000 miles mine had the same symtoms on the highway felt like i got hit in the rear then tried to accelerate and felt like misfire,would not accelerate, turned off for a few minuted then after restarted drives fine,checked trans fluid and was about a quart low (changed radiator and lost more fluid than i thought and never checked after radiator replacement) done a thousand miles since and no issues ,maybe some sort of trans protection buit in to prevent damage with low fluid hope this helps

My Truck 2005 Nisssn Titan 5.6 .thus is the 2nd time .When I put gas I see a Reflux and gas spill out of the Tank.Any advise to fix these . Thank you