Hey there guys, I have a problem on my hands, that even after searching around, I can’t seem to point myself in a direction to start. The codes seems simple enough being a P0121 tps code and a bank 2 lean code, but with some back ground info and the presence of too many questions, I really don’t know where to start. Here is the background on my situation and a little about my car. Sorry about the long post coming, but too many times I have seen not enough info as a response
My car has the following mods… tsp 231 / 237, patriot 5.3 stg.II’s, all the bolt-ons and a TNT F-1 kit. The last time I dyno’d I lost some power with the new rear end and ended up with around 428ish rwhp and 410 rwtq. The numbers under the big jets yielded me 593ish and 781. The torque was high even after smoothing. This was with 100 octane fuel… might have been 104, but 100 rings a bell. I brought the car home and it ran it’s first pass at the local track with decent results. Considering it was on worn out 26” ET streets and the small jets were put in, I spun the tires to a 7.201 @ 99.??. The car also ran NA that night with zero codes being thrown. Here is where I get confused. The only gas at the local track was 110. I was running on fumes when I got there so mixing with 91 wasn’t an option. I thought it would be extra safe. The usual codes came up on the way home that I was expecting of lean / bad 02 sensors. I was expecting this due to the fuel burning colder (as I was told). After I got about a mile or 2 from the track, the car started bucking, struggling, losing power, and feeling like a violent mis-fire. I immediately pushed in the clutch and watched idle to see if it was a broken valve spring / dropped valve, and the idle was fine. I revved the motor and everything seemed to go ok. I let out the clutch and with every sign showing normalcy, I punched it to see what the response was. Well tires went up in smoke like usual so I thought it was weird. Another mile down the road, right before my house, it happened again. This time it was hard to keep the car at a constant speed. The previous symptoms were back. Now take in mind this was all 6 months ago so if you have any questions please ask as it may jog my memory. I had a lot of goodies to install at my shop so I put off the tps problem until later. I then installed the bogarts, strange brakes, subs, cage, and a list of other things. Finally after 6 months the car hit the ground. This whole time I have been starting the car to keep the battery good and the motor lubed, but I never did run across another problem. not at idle, and not at part throttle. I thought it might be a fluke.

I took the car out last night for the first time since, and the code came back. Now I have read and searched this codes history in this forum and have a basic idea of things to do. testing voltage at different positions, doing a re-learn, replacing the tps (don’t want to do as I have seen it not fix things more than correct them) and lastly something about a setting change. I am not in possession of any tuning software (have lap top but haven’t decided on software yet), but I remember reading something about changing parameters from the stock tune.

So this brings me to here, asking you guys for the best starting place. Do you think that it might just be too high of an octane. I only run 10.8 comp. so even the 100 is high. I only used that for the spray. Do you think that by emptying the tank and getting something more down to earth would help? Another thing is the TPS itself… is it the sensor on the top or bottom of the throttle body? Do I disconnect them and then jump in between to find the voltage. I am not a guru when it comes to the electrical side of things but i do have an interest to learn. Even the basics I am missing. If you think it is this, could you break it down into 101 for dummy terms? I would really appreciate any help in this as the fact of something being wrong is really getting the better of me. Any and all help would be appreciated.

Thanks for going through the long read. I apologize for its length, but I wanted to paint a clear picture for everyone.

TIA, WOT

 

Was the 110 you put in at the track leaded or unleaded?

 

I was told unleaded. Is there a way of checking. It was pink in color (VP) and the guy that sold it to me said it used to be green???


Here is an update. I have since emptied the old tank of fuel and threw in a couple gallons of 91. Same symptoms as before.

 

Anybody else have any ideas or wish to help with the troubleshooting?

 

Too high octane should effect anything, all that does is slow down the combustion process. The TPS code is simply an electrical gremlin to chase down. What you will be testing is resistance, more specifically the change in resistance. A shop manual will give you the parameters and troubleshooting procedures.
The lean condition is more serious and may be related to the TPS issue. For instance you have your foot to the floor the TB is wide open but the TPS is only reading half throttle and only signalling for half the amount of gas that it really needs.

 

would you happen to know where a good place to buy these would be at and approximately how much they are???

 

To the top please.

 

The TPS code is common when a cam installed. You needed to change the values in the PCM to reflect the new idle of the cam. It sounds like when you added the 100-110, it fried your O2 sensors. I would replace the O2's, get a good tank of gas, and adjust the P0121 in the PCM.

 

i agree i might have fried them. sad because they were only a couple hours old. maybe 10 miles of use. as far as the values go, i have been running this cam since it came out a few years ago. do you think that it should have kicked this code sooner? i have broken down and ordered a new tps since i can't get an elementary instruction on checking the voltage. hopefully this will fix the problem.

do you think that a vaccum leak on the header Air gasket could cause the lean code as well? maybe cause a domino effect with the codes?