yea so i have heard.
So something is going on becuase there are loads of people getting 18 or so mpg with the same setup that I have. I am getting aggrivated at the jeep. I guess one day I will get a OBD2 scanner so i can see what is going on live with the vehicle

JrRifleCoach: if you want a little more power move that iat sensor into your stock air box or cold air intake. i added mine to my cold air intake and its got a small increase in power imo

OK so i ordered a CSF radiator today...... I am getting a thermostat to replace while I am at it. I guess the IAS anything else? Hoses are all new replaced the water pump 15k ago. I guess maybe a TPS.

Well today's MPG test was a bust as I drove about 30 miles in PT and FT 4WD through the snow.

Just love passing the id10T flatlanders with their pastie white knuckles on their heated SUV steering wheels.

Sweet..... I guess i will try it tomorrow.
I dont know what else to try

One option is to test the TPS with an analog vom meter. Just hook it up and watch the needle respond to throttle movement. The meter should follow the throttle. If its jumpy or unresponsive, time to replace.

FWIW, the IAT sensor replacement has shown an improvement. I will be trying Chrkee313's suggestion to relocate at a later date. For now I need confirmation the IAT replacement is valuable.

You said earlier that you replaced the O2 sensors with new ones and that you had a shop check the sensors. There IS a possibility that an O2 sensor is bad out of the box (albeit a small one), and that it's borderline to light up the CEL. Benchtesting an O2 sensor is tricky, I seriously doubt that the mechanic did anything else than hook up an OBD scanner to read codes. You said the plug(s) had black soot on them (incomplete fuel burning), so does the inside of your exhaust. It could be caused by an ignition problem (plugs, wires, coil(s)/coil pack) so that fuel isn't combusted sometimes, which makes it miss, and may ruin your cat in the process (see if it is glowing hot after a moderate drive). Other than that, leaky injectors can make it run pig-rich. Bad MAF/MAP sensors mess with your air/fuel ratio, but these usually thow a code. Can't hurt to check those anyway. I don't think that the timing is off, that's more common for DOHC engines with a timing belt. If the chain slipped by just one tooth, you couldn't drive the car. Thermostat stuck open? That would cause your car run in open loop, pig-rich. Replace, it's only a few $. Finally, the ECM could be malfunctioning. Only way to test is take a known good one and throw it in your car. Oh, and check for vacuum leaks (I think you did that with the starter fluid...)

Where is the IAT located?

I've got an 01, 4 inches and 31's, used to get 17 mixed, now Im down to 14.

02 sensors are stock, with 146K miles. It's so expensive to replace 4.

Has anyone tried replacing the cts ( coolant temperature sensor) or the manifold air temperature i am a obd1

What about wheel bearings, u-joints, draging brakes, transfer case type stuff?
I know my front wheels don't like to spin when I have it stands

I have replaced all of these components a few times.
It isnt glowing or even that hot. Just like everything else it. I do have a highflow cat I just have not put it in.


New injectors, but it was doing the same thing before and after injectors.

I dont know it will be changed in the next few days when I do my radiator

I bought one from a 00 that only had 2 o2 sensors, but it can barely run with this one in it. It over fuels like crazy.

I dont know I need to know this as well. I think right before the TB

Wheel bearing are new, u joints are new. Wheels spin and Tcase fluid is brand new.

OK so i replaced the air charge sensor. I didnt notice an increase in power. It went 65 at about 300 less rpms. I thought it was all good until I just got off of work and went to leave and the jeep wouldnt really go. I was pushing the gas expecting it to go and it just barely left until i got about 1/2 throttle then it just took off like i floored it... Any ideas?

Bad TPS? Fuel pump weak/ or cut out intermittently? Connections at the ignition system (plugs/wires/distributor/coil(s)/coil pack/CPS) loose? Bad or loose grounds? Corroded battery terminals? Vacuum leak? LOL could be a number of things, oh, and yes, if you change a sensor, especially one that meters air flow or pressure, it's a good idea to reset the ECM (disconnect battery for 1/2 hour). I have noticed on my old car ('91 SHO) that sometimes the ECM suddenly adjusts during a drive, can be quite scary
How does your car manage to go at a lower rpm at 65 without changing the gearing? Maybe the torque converter lock-up kicked in (O/D) and it didn't do that before because you had to put a higher load on the engine due to it poorly running? Actually, thinking about it, if you never get the torque converter lock-up to kick in (that is, over-drive), it would result in a considerable drop in fuel mileage, your original issue. Make sure you didn't switch it off, except when you're towing something or go uphill a lot.

so is it like you push the gas pedal and the engine is delayed in accelerating? if so it is probably your throttle body is dirty, take some carb clean and a toothbrush to it.

Have you reset the ECM since replacing the IAT? You know, pull the batt cable and turn on the headlights for a few seconds. Then hook it up and good for a nice easy ride.

Otherwise I'd be inclined to look at the TB and TPS more closely.