Q: Acceleration trouble.

asked by on January 20, 2017

I can't figure this out. My fiance's altima will not do more than 2500 rpm. As soon as u put it in reverse or drive it stalls out. It sometimes stalls out at red lights. Does a lot of jerking feels like its choking. I changed fuel filter and pump and pump strainer. It throwing two codes one for the MAF sensor and something about second gear ratio or something but i know that ain't the issue . So i changed the MAF sensor and air filter. Still nothing. It sometimes backfires right where the air filter is. I read numerous different things but idk what to do and I'm pretty good at figuring cars out. So could u please give me any suggestions?

My car has 122470 miles.
My car has an automatic transmission.

Hello, It sounds like the vehicle responds adversely to various loads being put on it such as sitting at the stop light and being put into gear. Both of these situations cause a load to be put on the motor that is more than when the motor is just sitting in park or neutral and idling. The MAP sensor is something that helps to relay information to the computer which uses this to adjust according to the load put on the motor. The Manifold Absolute Pressure (MAP) sensor senses engine load and generates a signal that is proportional to the amount of vacuum in the intake manifold. The engine computer then uses this information to adjust ignition timing and fuel enrichment. When the engine is working hard, intake vacuum drops as the throttle opens wide. The engine takes in more air, which requires more fuel to keep the air/fuel ratio in balance. When the computer reads a heavy load signal from the [MAP sensor]((https://www.yourmechanic.com/services/manifold-absolute-pressure-sensor-map-sensor-replacement), it adjusts the fuel mixture to slightly more rich than normal so the engine can produce more power. The computer will then retard (back off) ignition timing slightly to prevent detonation that can damage the engine and decrease performance. This may also be caused by other closely related components such as a dirty or failing mass air-flow sensor, a faulty throttle position sensor or potentially a vacuum leak. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing


Experienced Mechanic?

Earn up to $70/hr

What others are asking

Where are the LATCH lower anchors?
Your rear seats have four lower anchors that can be used with any LATCH (Lower Anchors and Tethers for Children) child restraint system. The lower anchors are located on each side of the rear outboard seats, where the seat cushion...
Engine seized in 2005 Acura TL
Hi. An engine replacement in your vehicle will cost between $2,000 and $4,000. This Depends on where the engine is installed and where the replacement engine is ordered from. The engine itself can range from $500 to $2,000. The labor...
Check engine light rough then goes away code cylinder 2 misfire changed plugs wires and cylinder 2 coil driving me nuts
The only things left to check is compression and the condition of the injector if you have changed the plug, wire, and coil. I would go with having the injectors cleaned. It is more likely that you have a clogged...
Issues with shaking in steering while driving - 1994 Ford F-150
Hey there. I would first look at tires and wheel balance, particularly if the tires have a lot of miles on them. Damaged tires (https://www.yourmechanic.com/article/how-to-check-if-your-tires-are-in-good-condition) can appear (on a balancing machine) to be balanced, yet they will vibrate terribly due...
Engine management light
Hello, thank you for writing in. If the code that was pulled pertained to the spark plugs and ignition system, then the issue may be related to the spark plug wires rather than the plugs themselves. Thsee can be inspected...
My car is idling very rough.
The idle air control valve is common for causing a rough idle in many cars, but it sounds like you have already corrected that. Another thing you may also want to check is the crankshaft position sensor. A crankshaft position...
I have Chevrolet Epica ls 2010 automatic 6 cylinder car. I want to change gearbox. Please tell me which car model's gearbox will fit to my car.
The gearbox (transmission) that is in your vehicle will fit the years 2007 through 2010 from the Epica, Daewoo, and Tosca. They all have the same manual 5 speed transmission.
driver side power lock doesnt work.
Thank you for writing in. There are several reasons you may be having these issues with the locks. However, without knowing what model of Chevy you are driving it is difficult to know what exact components you are working with....
No throttle response until warm, then not very good.
Hi there. The EBPV (exhaust back pressure valve) is sticking or the EBP (exhaust back pressure) sensor tube is wet which freezes in the cold preventing the EBP sensor from seeing the increase in EBP as you attempt to throttle...

Related articles

A Buyer's Guide to the 2012 Nissan Pathfinder
Whether Whether you have plans to go off-road or just want a vehicle that’s nice and roomy, the 2012 Nissan Pathfinder is definitely worth a closer look. Key Features As a dual-purpose vehicle, Nissan made the 2012 Pathfinder with three-rows...
2012 Nissan Altima vs. 2012 Volkswagen Passat: Which One Should I Buy?
Sedans are a special class of vehicle: created to provide a comfortable and often luxurious ride to those who have passed beyond the need to stick to the compact class. These slightly larger vehicles offer options the compacts and subcompacts...
The Best Used Cars to Buy If You Like to Go Off-Roading
Your Your best bet for off-roading is a 4x4 SUV. Depending on the model that pleases you most, though, you might have to shop around a bit to find a good used one. That’s simply because off-roaders typically become very...