Hi folks!! I ran Seafoam through my 1995 Maxima and a few days later it started developing a flat spot in the RPM range at 1800 RPM (like there was a rev limiter or something). It felt like a TPS failing, so I replaced it (which made the problem worse). I got a knock sensor code, so I replaced that. Still wouldnt rev past 1800 rpm, but I discovered if I unplugged the TPS completely it WOULD rev normally (albeit now with a very high idle and TPS codes). I then replaced the TPS again (to rule out getting a bad new one), to no avail. I cleaned the MAF sensor, disassembled and cleaned the ICAV, checked all hoses and the throttle plate, with all seeming to be in good condition. It now runs normally through the RPM range (with the TPS disconnected), but idles at 1800 rpm in gear & rolling. If I stop the car and put it into neutral, it drops down to about 1100, but that climbs right back up when I put it in gear. I assume the idle issue is caused by the TPS being unplugged, but why wont the car rev past 1800 RPM with it plugged in and idling normally?

Appreciate any and all help, thx......

 

BTW; I also disconnected the battery for a few hours to reset the ECU, and then performed the throttle learning technique by turning on the key and depressing the accelerator pedal 5 or 6 times.......

 

is the TPS set correctly?

 

I am going to doublecheck it via multimeter tommorrow (in 120 degrees no less). But with it plugged in would being set incorrectly cause the 1800 rpm limit?

Sweet Max in your profile btw....... :-)

 

this is another WWWD, search, i recall reading something about this just a few days ago

 

I'm sorry; WWWD? Apologize for the newbie ignorance....:-)

 

if the tps and throtle are not ligned up it could cause a discrepincy between the tps and other sensors. in theory, this could cause the ecm to go into limp mode. however, this would normaly set some codes.

 

OK, quick update. It actually WAS 120 degrees today here in AZ, so I didnt use the multimeter yet. I have somehow (dont ask me how) now lost the 1800 RPM limit with the TPS sensor plugged in. The only issue left is that I have a high idle whenever in gear or rolling. When I'm stopped and in neutral, it idles normally. Throwing me a PO120 code, so I am hopeful using the meter will help. Just still find the high idle when in gear or rolling to be very strange........

 

there a member called the Wizard, hes always suggests searching every topic before posting, and i learned that its the best way to go about anything, so its stands for what would wizard do...

 

Yup; searched it backwards & forwards and never found a single thread where the idle was going up & down either placing car in gear or because it was moving. Sure wish I knew what thats all about.... :-)