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Is yours automatic Transmission???? I am going to assume it is, from your shifting comment.
Mine (AW4 Automatic) had no guts and no power (and other issues) when I bought it 12 years ago, my 87 Wagpneer.
Over the years I found one thing after another, some by shear accident that were causing the problem.
When I first bought it the Cat was clogged up. Took me three years to discover in my R&D that the category and aftermarket had no idea how to properly test a Renix TPS. Google "Ecomike RenX Files" for the 1 year story.
Turns out the TPS has 2 separate sensors. If they get out of sync the transmission may shift fine, but can shift late or too early. Mine never got over about 1200 rpm at WOT, took 3 minutes to get to 60 mph at WOT. I would be in 4th gear in 30 seconds doing 25 mph at WOT!!!! So yes it can have a huge effect. The problem was the Tranny side of the Renix TPS on mine only had about 30% of the span of a good TPS so shift way too soon and never got into the power range at 1500 to 3000 rpm
But the TPS passed all the various known versions of testing and calibration. A New TPS fixed the early shifting problem, I could now get up to 60 mph in reasonable amount of time, but it still had no real power like my other Renix rigs when I would go WOT doing say 35 or 55 mph.
Fast forward 11 years and by shear accident using my Snap-on MT-2500 I discovered the TPS did not have a complete % open span from min to max. The TPS was not the problem, it was good. The damn 90* rod on the side of the throttle body was not shaped properly anymore (PO issues) and was stopping the throttle body from getting past 58% of WOT according to my Snap on MT-2500 scanner. Looked tat the rod on my other 2 Renix jeeps and sure enough the 90 degree bend was about 70 percent on the problem jeep, and so the TPS sensor was not sending WOT data to the ECU and the throttle plate was only 58% open at WOT as the gas pedal could not push it further as the linkage could not move any farther due to the bent rod. It was the 90 degree rod with the black past press on grips on the side of the throttle body that was partly straightened out, limiting its movement to shorter path. Figured that out just 3-4 months ago.
Makes me wonder how many seemingly gutless engines got swapped over the years to replace a bent $1 (junk yard pull) rod, LOL.
Mine is 135-150 psi compression 292,000 miles and had as much power as any Renix I ever drove once I bent the rod back to its OEM shape using one from my other rigs as a guide. Real Dirty air filter can hurt power too, but I doubt you have overlooked that.
Too little fuel at high demand from a leaking hose on the output of the fuel pump inside the tank can cause low power too.
Smog test does not test acceleration and power, it is a static rpm test. The MAP signal is supper important when the throttle moves a lot real fast!!! So is the TPS signal!!!! In fact if the ECU side of the TPS can only from 17 to 50% of WOT, due to it being bad, it can cause low power and running issues as well.
MPG problems are usually the O2 sensor, but my bad TPS and bent rod cost me about 4 mpg each, and my bad O2 sensor was another 4 mpg lost!!!! I was getting 6-8 mpg at the worst before I replaced the TPS and O2 sensor.
Mine (AW4 Automatic) had no guts and no power (and other issues) when I bought it 12 years ago, my 87 Wagpneer.
Over the years I found one thing after another, some by shear accident that were causing the problem.
When I first bought it the Cat was clogged up. Took me three years to discover in my R&D that the category and aftermarket had no idea how to properly test a Renix TPS. Google "Ecomike RenX Files" for the 1 year story.
Turns out the TPS has 2 separate sensors. If they get out of sync the transmission may shift fine, but can shift late or too early. Mine never got over about 1200 rpm at WOT, took 3 minutes to get to 60 mph at WOT. I would be in 4th gear in 30 seconds doing 25 mph at WOT!!!! So yes it can have a huge effect. The problem was the Tranny side of the Renix TPS on mine only had about 30% of the span of a good TPS so shift way too soon and never got into the power range at 1500 to 3000 rpm
But the TPS passed all the various known versions of testing and calibration. A New TPS fixed the early shifting problem, I could now get up to 60 mph in reasonable amount of time, but it still had no real power like my other Renix rigs when I would go WOT doing say 35 or 55 mph.
Fast forward 11 years and by shear accident using my Snap-on MT-2500 I discovered the TPS did not have a complete % open span from min to max. The TPS was not the problem, it was good. The damn 90* rod on the side of the throttle body was not shaped properly anymore (PO issues) and was stopping the throttle body from getting past 58% of WOT according to my Snap on MT-2500 scanner. Looked tat the rod on my other 2 Renix jeeps and sure enough the 90 degree bend was about 70 percent on the problem jeep, and so the TPS sensor was not sending WOT data to the ECU and the throttle plate was only 58% open at WOT as the gas pedal could not push it further as the linkage could not move any farther due to the bent rod. It was the 90 degree rod with the black past press on grips on the side of the throttle body that was partly straightened out, limiting its movement to shorter path. Figured that out just 3-4 months ago.
Makes me wonder how many seemingly gutless engines got swapped over the years to replace a bent $1 (junk yard pull) rod, LOL.
Mine is 135-150 psi compression 292,000 miles and had as much power as any Renix I ever drove once I bent the rod back to its OEM shape using one from my other rigs as a guide. Real Dirty air filter can hurt power too, but I doubt you have overlooked that.
Too little fuel at high demand from a leaking hose on the output of the fuel pump inside the tank can cause low power too.
Smog test does not test acceleration and power, it is a static rpm test. The MAP signal is supper important when the throttle moves a lot real fast!!! So is the TPS signal!!!! In fact if the ECU side of the TPS can only from 17 to 50% of WOT, due to it being bad, it can cause low power and running issues as well.
MPG problems are usually the O2 sensor, but my bad TPS and bent rod cost me about 4 mpg each, and my bad O2 sensor was another 4 mpg lost!!!! I was getting 6-8 mpg at the worst before I replaced the TPS and O2 sensor.
I didn't think the TPS had that much effect on power. I knew it effected shifting, which is fine. Last time I checked it it was fine. And if the MAP was bad it would run like poo which I would think would show up on a smog test