My jeep is weak. Going uphill it shifts down but will not pull. It is useless with trailer behind. I get about 12MPG city. It sputters and I get a little vibration under load, as if it is not firing all cylinders. It also smells gasoline after stopping. It feels more responsive just after starting while still cold. Could it bee vacuum? New plugs and plug wires, no fix. Rotor and lid looks fine (but could be a crack that opens while hot?). Help!
Remove the vacuum hose from the fuel pressure regulator.
https://www.rockauto.com/en/moreinfo.php?pk=10893392&cc=1181483&jsn=387
If gas leaks out, the regulator is leaking, and that’s why you get lousy gas mileage, and why the engine lacks power.
Tester
I presume you have the 6 banger. There’s been some recalls on the O2 sensor, wiring harness, and exhaust manifold, so make sure those have been done. There’s one on interference between the intake manifold and fuel line too, so double check that. There’s a tsb on misfires, caused by the alternator or throttle position sensor. Worth a check.
Low power can be caused by all sorts of things. If nothing else is obvious, all the routine engine maintenance is up to date, ask your shop to measure the cylinder compression. Your Jeep engine may just be plumb worn out and in need of a rebuild.
If I had that problem and the post above didn’t pan out I’d replace the spark plugs, dizzy cap, rotor, spark plug wires, and test the egr function to get started.
Are you doing regular maintenance and work on it or just driving it until issues arise? I had a 1990 Jeep Comanche that was stolen out of the driveway at night like 5 years ago. Still pisses me off to think about it. Sometimes I thought it spotted it repainted or something.