Hi everyone. So I have a 1998 Cherokee Classic.

I have done some work to it just to get it 'tuned up' to say. I got new tune up kit(spark plugs, wires, etc), fluid changes, etc. Then what I had done was put in a new Cat and new O2 sensors (Had a CEL(forget the code because this was a month or so back) but the guy said the CEL said basically the cat and or the O2 sensor was bad). So I put in a brand new cat and two brand new 02 sensors. Everything was fine for a month or so, but I did seem to have a bit low gas mileage.

Then a couple days ago I was on a 3 hour drive and during the drive my throttle seemed to stop responding a couple times. I would be holding the gas down going 65mph, then all the sudden it would feel like I had no throttle, and I would start to slow down. I would let go of the throttle, and then push it down again, and after doing that a couple times, it would start to drive normal again. I also heard a bang or knock once or twice, which I have never heard before. The CEL also came back on.

So today I went and got a new TPS sensor put in because after reading some forums that was something that was suggested to replace in similar situations. So when I got the TPS sensor put in, the shop checked the code and said it was giving a code saying that it was running rich and probably a bad O2 sensor. Now I just put in two brand new O2 sensors about 1 month prior, along with the new cat, so that confused me. After I left the shop, the CEL came on again, almost instantly, and, on the drive home I noticed something odd. I was driving about 45mph and I found when I let off the gas pedal, my RPM's went down to 700. The car kept coasting around 45mph, but the RPM's down at 700 with foot off gas, then when I touch pedal again, RPM's ramped up around 2.5k. Never seen that happen in any car I had, but just happened on short ride home today after TPS put in.

So now I don't know if the new TPS I put in is acting funny, if one of my o2 sensors I put in was defective, or if it is some other problem.

Anyone have any advice where I should go from here?

Thanks!

 

So I did some research online and I found that a bad MAP sensor can cause low gas mileage, chugging/sluggish throttle control, and even set off an O2 sensor code due to it sending too rich fuel through.

So I just ordered a new map sensor and will have it put it when it arrives in two days. I hope that solves the problem.

The only thing I am concerned about(until MAP is in and I see if that works) is that my new TPS sensor I put in today seems to be causing weird RPMS. Normally if I am cruising along in my Jeep(or any car) and I let off the gas, the RPM's stay around what they were at when I was holding the throttle(then slowly goes down as I am not giving any gas/throttle)... well after putting in the new TPS today, like I stated in my last post, I find that when I am cruising and let go of the throttle I find the RPM's instantly drop to around 700, almost like I am in neutral, and when I hit the gas again, it picks back up to the RPM needed to continue at speed(2.5rpm or whatever is needed for the speed I am going). Never seen that happen. So I am thinking in trying to solve one problem by replacing the TPS, I may have created a 2nd problem... not sure...

Thoughts anyone?

 

is the TPS in correctly? it can go in in more ways than one. the directions will tell you how to install it. check it out.

 

I can only assume the shop that put it in installed it correctly. They removed the old one(so they should have seen how it was installed).

But I will look into that. So you are saying that even if it is installed incorrectly it would still 'work' just not correctly?

 

this may help you..

 

you can have leaking injector or bad pressure regulator, you have to giagnose first, replace parts later.

 

While you're in there checking the TPS, give the whole throttle body a clean. You want a soft tooth brush and some throttle body cleaner. If it's never been cleaned before, take the throttle body off as you don't want a bunch of black good falling into the intake. This will give you access to the butterfly valve, MAP, IAC, and TPS. Clean them all very gently and reassemble. If you're careful enough you can even reuse the gaskets! You may not need a new MAP, it could just be filthy.

Once you have the TB back together give this a spin: https://www.cherokeeforum.com/f2/free-quick-fix-41821/

 

Thanks for this, it was easy and saved me $40 to $50! After the new TPS was put in, I had wacky RPMS and my jeep even dropped down to 0RPMS a couple times and died. I got a new map sensor, and I put back in my stock TPS sensor myself, it was easy, thanks again for that video!

I reset the CEL by disconnecting the battery while I worked. After I was finished with the install(new MAP and stock TPS) I went for a 15mile drive, and it drove perfect and no CEL came on(for the past couple weeks, CEL would come on within 30seconds of starting the car after being reset). So it seems for now it is driving perfect!

Now I just hope it continues to drive perfect for a long time.

 

Jeeps ran perfect for 40miles now

I think all is good for the time being! I do plan to clean the throttle body soon just as an extra precaution because my Jeep has about 170,000miles so it is probably dirty(I haven't look yet, I can only assume).

 

sounds like the TPS was not in correct.
glad it worked for you. you should be good to go.