Q: My car is having trouble turning over and when it does it can only go 20 mph max but I can't go uphill. What could be the issue?

asked by on August 02, 2017

Car won't go over 20 mph and is having trouble turning over. It also can't go uphill
My car has an automatic transmission.

It sounds like you may have a catalytic converter that may be clogged or failing. There are a number of reasons that may cause the catalytic converter to fail. They include: O2 sensor, fuel injectors, spark plugs, EGR valve system, exhausts manifolds, vacuum hoses, and MAF sensors. I would suggest having all of these components checked to be sure they are operating correctly. Generally, when the motor is continuously running too rich (too much fuel), this will ultimately destroy the internal components to the catalytic converter by way of igniting raw fuel inside the catalytic converter. Despite the catalytic converter’s ability to withstand very high temperatures, excessively rich fuel conditions can produce enough heat to push the converter material beyond it’s limits. These types of rich fuel conditions result in higher than normal temperatures that can cause matting erosion and burn away or melt converter coatings. If temperatures are high enough, the ceramic substrate itself will melt and clog. I would suggest having an expert from YourMechanic come to our location to inspect your vehicle.

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