98 Ram 5.2 OBD II TPS/Spark Adv Values

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Deadwood777

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Aug 9, 2014
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Ram Year
1998
Engine
5.2
I have a '98 Ram 1500 5.2L automatic. Recently purchased with 135K miles on it. Very sluggish performance. Pedal almost to the floor to hold 75 on the interstate, and it want's to nose-dive into 3rd, or even 2nd if I step into it too hard trying to hold speed up a hill. There was just nothing there. The MIL is not on. I bought a half-way decent OBD II/CAN scanner with live data anyway. No DTCs stored or pending. Everything checks out running the tests. I next did a compression check with 150psi all the way around. Plugs looked a little lean to me, but not bad. Definitely not running rich. I then did a full ignition tune up. Performance increased substantially after the tune up! It still seems a little lacking in the horsepower department, though. Not bad, but not a lot of power until it hits about 3K rpm, then it screams. The OBD II scanner says the O2 sensors and cat are OK. Viewing live data on the scanner, key on, engine idling at running temp, it shows the TPS at 12.9% with a closed throttle. Running 50mph up a steep grade with my foot almost to the floor, it's showing 60-70%. I tried to get a WOT reading but the sample rate on my scanner is slow and I didn't want to over rev. Also, at idle, the spark advance seems to jump around in the 10 to 19 degree range. Are these normal values? Shouldn't the TPS be at 0% at closed throttle and 100% at WOT? I haven't put a meter to the TPS to check the voltages yet. Does the spark advance jumping around indicate a problem or is this normal? Any advice on where to go next would also be greatly appreciated. Thanks in advance for any help...
 
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crazykid1994

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Sep 21, 2013
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Location
Florida
Ram Year
2017
Engine
Hemi 5.7
Never had this issue but maybe try the tps. Might be reading wrong. Truck is cable throttle so if your cable is taught and operating properly but still shows those readings may need to try changing the tps just to be safe. Also try cleaning the IAC area to make sure it’s clean. Alcohol and a small rag. Pull the throttle and remove the iac. Mine gummed up and had issues while idling. Do not clean the iac valve with spray. Just wipe it a little. And do not force it to move as you could damage the servo inside. This is a really old thread. Lol
 

dapepper9

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Feb 7, 2013
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Location
Iowa/Nebraska Border
Ram Year
2001
Engine
5.9L V8
Tps readings are normal. Straight zero and straight 100 aren't a thing. Idle spark is close. Factory commanded idle spark is 16 degrees

How did cylinder 8 plug look? Any oil fouling?
 

L33smith

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Aug 13, 2022
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Location
San diego, ca
Ram Year
1999
Engine
5.2l
Deadwood did you ever figure your problem out? I'm having the same problem but spark is 13.5-20°
 
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