SUV has problem getting up to 30 40 mph

350,000 MILES • 5.3L • V8 • 4WD • AUTOMATIC
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MJWSR
  • MEMBER
  • 1 POST
Hard to get vehicle to go, can be turned off and restarted to go for a bit, then struggle to go.
Took to nearby rpm shop, they say it's the transmission.
I drove recently over 50 miles around town and on freeway, no signs of transmission problems.
I had front end alignment done maybe 1,500 to 2,000 miles ago, the mechanic drove it around to check on front end , no problems in transmission then were noticed.

I suspect the catalytic converter.
Rpm says that's not the problem.

My grandson drives it daily on interstate highway 60 miles round trip to school.
Was driving it.
Jan 6, 2020 at 5:15 AM
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ASEMASTER6371
  • ✓Experienced Mechanic
  • 52,796 POSTS
Good afternoon,

Yes, it could be but needs to be tested to confirm.

A back pressure test will confirm if the catalytic converters are clogged. You remove the O2 sensor and insert the gauge. If it read above 1 pound, the catalytic converter is clogged not allowing the engine to breathe.

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

Roy

Jan 6, 2020 at 6:21 AM
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