Hey all,
I’ve gotten to the point where I think I’ve exhausted testing all the causes for why my Jeeps acceleration is slow as balls in anything other than 1st gear. I’ve read as many forum threads as I could but I’m truly stumped. Here are the details:
Vehicle specs:
2003 2.4L SE
Initial symptoms:
Last fall I noticed on rare occasion there was this “popping” noise coming from the exhaust manifold side of the engine when I would accelerate, as if there was a backfire. This slowly became more frequent until I began to experience rough idle accompanied by bogged acceleration.
After testing the spark to each spark plug and changing nothing the backfiring/rough idle went away on its own but the poor acceleration remained.
No codes/CEL
It starts and idles fine! No high or low RPM. Bogs down when under heavier load, I.e. accelerating in 2nd,3rd,etc.
It’s not my 33” tires either. I drove it 6 months straight without any issues.
It was put away for the winter and here is what I’ve done this spring so far with no success:
Part Replacement:
Testing Done:
I’ve gotten to the point where I think I’ve exhausted testing all the causes for why my Jeeps acceleration is slow as balls in anything other than 1st gear. I’ve read as many forum threads as I could but I’m truly stumped. Here are the details:
Vehicle specs:
2003 2.4L SE
Initial symptoms:
Last fall I noticed on rare occasion there was this “popping” noise coming from the exhaust manifold side of the engine when I would accelerate, as if there was a backfire. This slowly became more frequent until I began to experience rough idle accompanied by bogged acceleration.
After testing the spark to each spark plug and changing nothing the backfiring/rough idle went away on its own but the poor acceleration remained.
No codes/CEL
It starts and idles fine! No high or low RPM. Bogs down when under heavier load, I.e. accelerating in 2nd,3rd,etc.
It’s not my 33” tires either. I drove it 6 months straight without any issues.
It was put away for the winter and here is what I’ve done this spring so far with no success:
Part Replacement:
- Spark Plugs - Champion 7570
- TPS sensor
- MAP sensor
- IAT Sensor
- Bank 1 upstream O2 - NTK 23138
- Crankshaft position sensor (CKP) - standard motor PC386
- Fuel pump and filters - Bosch 69316
Testing Done:
- Plugged cat testing - I’ve test driven the Jeep with the O2 sensors unplugged and separately test drove it with the lower half the exhaust disconnected at the intake manifold.
- Plugged cat inspection - just to double check I fed a wire cam to look at both cats, they look fine to me.
- Cleaned throttle body
- Cleaned battery terminals
- Measured battery voltage - 12.5 V
- Measured alternator voltage - 14.5 V when running
- Unplugged battery to reset computer.
- Swapped ignition block from my dads running 2.4
- Inspected spark plugs for fouling
- Test drove with air filter removed.
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