FERM and any other Jeep guys......

[THEFERMANATOR]

If the tranny was low it could throw a code for slippage. As far as actual fluid level's, that would be a no. Brake fluid though will turn on the brake light in the cluster as the proportioning valve will trip the limit switch if it gets low or air in it. Reading the codes is really your only option to go with. Be careful though of the light when trying to sell it. If it is an OBDII readiness monitor that is throwing it, it will trigger the light after a highway drive. MOST codes will clear themselves after 3 consecutive engine heat cycles without the fault being present. The downstream O2 is famous for driving people nuts with an intermittent check engine light. I don't remember where the ground is at on a 99, but I know they give trouble with the ground for the downstream O2.

[C YENSEN]

well boys.....i took the battery cable off last week for an hour like I mentioned and the light is off...... I have driven it 55 miles and started it at least 6 times since then......I think I won

[C YENSEN]

well stopped at autozone and the check engine light is due to the throttle position sensor and a loose gas cap or vacuum line. looks like some good old WD-40 should fix the first problem (throttle has been sticky lately), and the second should go away if i tighten the cap a little more......at least i know what it is now

[THEFERMANATOR]

TPS is sealed, so I doubt spraying it down will help any. Replacement is about the only option on them. As for the other code, are you sure it was for a loose gas cap? Did they give you the P codes? The idiots at autozone once tryed to sell a buddy of mine a distributor for a shift solonoid code. Like I said earlier, i don't remember 99 having a leak detection pump. It was probably a fuel vapor purge solonoid code which is not an uncommon failure item. Always check what the P code is, don't trust the AUTOZONERS to tell you what is wrong. Get the code and check it yourself. I use em just to get the P codes and then go and figure it out from there. I'm to cheap to spend the money to get a scanner when I don't check but 3 or 4 OBD2's a year as all of my stuff is ancient.

Does your gas cap have a warning on it in regards to if you leave it loose it may turn on a check engine light?

[tsubaki]

Be sure and wipe the thick varnish from inside the butterfly location of the throttle body. Laquer thinner or WD40 should take it off, that will slightly improve idleing and takeoff.

[C YENSEN]

autozone printed out the codes for me. the gas cap was #123 (or loose vaccum line) and the TPS was #455. cleaned up the cable and throttle body and sprayed her down with WD40 and i think it worked. the trottle is no longer sticking like it was. as far as the gas cap. when i replaced the exhast manifold last week I missed a vaccum line when i put her all back together.

light is still off but who knows

[THEFERMANATOR]

Originally Posted by C YENSEN

autozone printed out the codes for me. the gas cap was #123 (or loose vaccum line) and the TPS was #455. cleaned up the cable and throttle body and sprayed her down with WD40 and i think it worked. the trottle is no longer sticking like it was. as far as the gas cap. when i replaced the exhast manifold last week I missed a vaccum line when i put her all back together.

light is still off but who knows

#1 I'm going to ASSume that the codes were P0123 and P0455? And #2 I'm going to assume that you got the codes reversed? If this is correct then the P0123 is for an open circuit in the TPS that allowed more than 4.50 V to be present at the sense circuit in the PCM. This would be a sure sign of a loose connection at the TPS, a bent prong inside the connector, or a failed TPS. The P0455 is for a large leak in the EVAP purge circuit. It says that yours uses a basic LDP with a vacuum switch and the purge solonoid to supply the pumping. Trace the large heavy guage vacuum line under the hood that runs over to a black solonoid. The vacuum line at some point will have a green test port cap on it, and it should tie into your vapor cannister which is a rectanguluar plast canister that was mounted under the hood on the passenger side on alot of them.

[C YENSEN]

Ferm you are right on all accounts got the numbers mixed up sorry. well she is still acting up choking, stalling, spitting, sputtering. I am going to get a new TPS at advance today (if they have one) and put it on tonight. Looks like it is only two screws. pretty sure i got the vacum line thing taken care of. like i said i forgot to put one back on.

thnks

[Stillrunning]

My check engine light has been on for about 2 years so I keep checking the engine and its still there.

[THEFERMANATOR]

You'll need to do a reset on it after replacing the TPS, so disconnect the battery for at least 30 minutes after replacement.