Deadwood777
Junior Member
- Joined
- Aug 9, 2014
- Posts
- 2
- Reaction score
- 1
- 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...