Read all the posts still need help

[Tom M.]

Heres the problem. I have a '92 xlt 2wd with 4.0. When the truck gets warmed up the idle at jumps between 500 & 700 rpm when stopped then hesitates till it gets above 2000 rpm. The whole truck starts rocking unless I put it in nuetral. I cleaned the MAF that helped just a little bit. I am wondering how you can tell if the MAF is cooked or not. Unforunately I do not have a code chaser to read what the computer is reading. Any help would be greatly appreciated. Is there anything else I should look at?

Tom M.

 

[CHH777]

Disconnect the battery for ~20 min to reset the computer. If you still get CEL you can pull he codes with a paper clip. Do a search on how.

 

[fordkrazy]

is it running hot? cause mine did that exact thing when it was overheating. the computer starts droping cylinders when it gets real hot. if you dont have a check engine light on then the paper clip trick wont help you any. you really should get a code scanner that can do engine running tests.

 

[Tom M.]

Actually the check engine light came on & then went off. It has done that twice. Also when it starts jumping the battery needle jumps. It has a new battery & I replaced the posts yesterday. The temp stays at 3/4 but I have a tranny cooler mounted right to the radiator that I have not had time to remount yet.

 

[arsoul]

I'm having sorta the same thing with my X. After its all warmed up, she runs fine, until I come to a stop. Then it starts idling rough, around 200rpm, then dies, unless i put it in nuetral. Almost like the engine is starving for air.
I've cleaned the air filter and the MAF, still no change. The check engine light comes on everynow and then. I pulled the codes and I got 'hard engine' or something like that. I haven't a clue what it means.

 

[SteveVB]

Throttle Body?

Take a look at the throttle body and IAC valve, clean them and test. Check that the intake hose from the MAF to the TB is on tight.

 

[PunkChild]

anyone think of changing their oxygen sensors? It could be a possible problem.

 

[fordkrazy]

i didnt think of this before but if you have the automatic the thing that controls the torq converter lock up could be stalling the engine. also when you say 3/4 to you mean 3/4 of the way to the H? if so that is way hot. mine runs arround 200 degrees with the factory guage between the n and the o of normal. mine may be calibrated different than yours. still if mine got that high the overflow tank would boil over. also if you have intermittant CELs then you should get a code scanner to do an engine running self test. it will tell you if it cant control the IAC properly or if it is recieving out of range values from differnt sensors. it will also do a cylindar balance test where it starves one cylnder at a time to determine which one is the weakest if any are.

 

[mdrut]

Best thing to do is go get a code reader..Cheap one at wal-mart is $30 and this is the one I and most of the others use..Save yourself time and money before it's overwith...Sounds like vacuum, but it could be anywhere..the reader will help you pinpoint the problem..It's not the torque converter..They work off of rpm and centrifical force..

 

[Tom M.]

I just bought this thing & I am sure no services were ever done it still has the original plug wires. I am changing the fuel filter, air filter, pvc valve, oil, & the plugs & wires. I will go get one of those code readers tonight. Does the reader just give numbers & I have to get a trouble shooting manual seperately to tell the codes?

 

[mdrut]

Mine came with the book...There is a site that tells what the codes are, but I don't know it..Just post the code and I'm sure someone will get back to you...

 

[Pete]

Get the code reader. You won't be sorry you did. It's one more tool to help you become master of your machine and not the other way around.

The other critical thing to remember here when troubleshooting is if the code reader shows no codes then your problem is with some component or system that does not talk to the EEC. This sounds bloody obvious, and it is, but it is critical when troubleshooting. For example, that is how you know to look for such problems like clogged catalytic converter, bad ignition module, bad plug wires, stuck thermostat, bad fan clutch, or bad fuel pressure regulator because none of those items will generate a code in the EEC. Once you get no codes from the EEC you at least know where NOT to look for the problem.

 

[Tom M.]

This is a stupid question but where is the computer located on the '92 x.? Does the coder plug directly into it?

 

[Pete]

The code reader plugs into two female wire connectors under the hood on the right side. One is grey and is sort of trapezoidal-shaped. The other is a single-wire black connector. On my '91 they are located sort of in that mess of wires between the blower motor and the fuse/relay box, just above the fender. The computer itself is physically located behind the right side (front passenger) kick panel. You will not accerss the computer itself when using the code reader.

The instructions that come with the reader have pictures of all this so don't sweat it. This information is also in the repair manuals. You do have a Haynes or Chilton manual, don't you?

 

[Tom M.]

That helps alot. Acutually I am getting my Haynes manual for the x tonight on my way home. I wonder if they have a trade in program for all my other manuals, on the vehicles I dont have anymore. I almost need a bookshelf for Haynes manuals. LOL!

 

[Pete]

Sell 'em on eBay ! ! !

 

[TDG]

Re: Throttle Body?

Originally posted by SteveVB
Take a look at the throttle body and IAC valve, clean them and test. Check that the intake hose from the MAF to the TB is on tight.

Also make sure that the intake hose isn't cracked at the bends, take it off and look at the ribbed areas against strong light, if you have cracks you will see them. Years of the engine shaking the intake tube against the air filter box will cause cracks in it, happened to my 92.

 

[Tom M.]

Well I have to say this has been very helpful. I got the coder it read the o2 sensor. Not trusting the computer I proceeded to replace the MAF the IAC & the Throttle speed Sensor. Well none of this worked at all. Of course I took all those parts back. Then it hit me like a baseball in the face, from Randy Johnson. A vacum line had cracked & came loose from the emissions canister. I replaced the vacum line & problem fixed. She now purrs like a kitten. Again I appreciate all the input & advice. You guys are the greatest! By the way I still had time for some romping with the wife & kids. Thanks again.