Q: Intermittent throttle position vs acceleration -- either a lot or a little to accelerate from a stop and maintain speed.

asked by on February 10, 2017

mostly truck requires what i consider a lot of pedal push to accelerate from a stop and maintain speed. occasionally it drives "perfect". the amount of throttle to accel and cruise is normal to me.

I considered closed/open loop issues but the issue occurs at any time cold/hot or otherwise I incorrectly identified the map sensor as being bad (didn't account for altitude) and so replaced. After getting tired of researching egr valve as a possiblity I swapped it with a new one. I've done a vacuum check and fuel pressure check. fuel pressure was at 56/58 for [on not running]/[idling] all checked out.

possible related issues

engine does a single "shake" occasionally

also when cruise is set and truck reaches 5th gear it will refuse to down shift unless speed drops by 5 at which point it down shifts 2 gears. Cruise responds normal as long as it doesn't reach 5th gear and TC lockup. Took voltmeter to throttle controller and noticed wide open throttle yet still no down shift

My car has 160000 miles.
My car has an automatic transmission.

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

Front differential
The front differential has a purpose to propel the front wheels, in turn giving your Mercury its 4 wheel drive capability. If you are experiencing abnormal rotational sounds or a clunking or banging during acceleration or deceleration while the 4...
Engine knock and hesitation
The poor acceleration and misfiring can definitely be tied to the[clogged catalytic converter, but something had to clog the converter. In many cases, oil entering the exhaust or too rich of an air/fuel mixture can overwork the catalytic converter to...
Traction light/reduced engine power and check engine light coming on
Hello. From what you describe, it would appear that your vehicle may be experiencing some sort of intermittent wiring or sensor issue. If the problem occurred again after driving over a bump, then it may be possible that a damaged...
New rear disc rotor/Hub/Parking Brake
Hi there: In general, there are a few things that can cause the brake rotor (https://www.yourmechanic.com/article/how-long-does-a-brake-rotor-disc-last) and wheel to not spin freely after installing a new rotor. The first and most common is that the center hub is dirty, rusted...
Engine light on
Your check engine light (https://www.yourmechanic.com/services/check-engine-light-is-on-inspection) may come on for many different reasons such as a faulty mass air flow sensor, a faulty O2 sensor, a bad catalytic converter, bad spark plugs or wires and many other reasons. Unfortunately due to...
Rough idle when stopping or at complete stop.
Shaking or vibration (https://www.yourmechanic.com/services/engine-is-shaking-pulsating-or-vibrating-inspection) may be caused by many different things such as faulty spark plugs, poor fuel pressure or misfires. Other things such as a faulty idle air control valve (https://www.yourmechanic.com/services/idle-control-valve-replacement) may cause the engine idle to drop below...
Timing chain, camshaft and crankshaft timing problems 2006 Dodge Ram 4.7L
Hi there - there are "camshaft timing tools" specific to every engine which are used for camshaft component repair to avoid just this scenario.These specialized tools keep the camshafts and crankshaft locked in the proper position ("crankshaft top dead center",...
Car doesn't start but cranks
You mention "adding" gas to the tank. If the tank was run dry, the fuel pump could have been damaged and, in that scenario, yes the pump should be tested to see if that is the problem. If, by chance,...
to pass smog check P0420 catalyst system efficiency below threshold bank 1, what is the total cost of repair
Hi there. Typically the P0420 OBD II trouble code (https://www.yourmechanic.com/article/p0420-obd-ii-trouble-code-catalyst-system-efficiency-below-threshold-bank-1-by-jamahl-walker) is caused by a faulty catalytic converter, however it can also be due to a worn out front bank O2 sensor, faulty rear O2 sensor or damage to wiring harnesses...

Related articles

A Buyer’s Guide to the 2012 Dodge Charger
If If you’ve always loved driving performance cars but you don't know how you’ll fit a baby seat in a Mustang or a Camaro, the 2012 Dodge Charger could be the car for you. While it has the room and...
Symptoms of a Bad or Failing Throttle/Accelerator Pedal Position Sensor
Common signs of a faulty pedal position sensor include inconsistent engine response, reduced fuel efficiency, and the Check Engine Light coming on.
The Most and Least Expensive Cars to Insure
Car insurance quotes depend on the car make and model. The Honda Odyssey is the least expensive and the Dodge Viper is the most expensive to insure.