Makomike

Hi guys/gals I'm working on a 93 T4R with a 3.0 that will buck, stutter and acts like it is pulling a horse trailer from idle to 3k rpm and above 3k rpm it runs like a turbo kicks in. Unfortunately it will sometimes drives quite well. If I shut the motor off and start it again while driving it will sometimes start running great. Weird problem/symptoms. Mileage is in the toilet at 12mpg. It is a 5 speed. I have done the head gaskets, timing belt, plugs, wires, cap, rotor and air and fuel filters and I have replaced the TPS and adjusted on the bench. I am convinced that it is set correctly. The idle jumps to 1800 with it unplugged. still have the issue. Also, after starting up again with a warm engine the idle may jump around from 200 to 1800 rpm still drives fine other than no low end power and occasional bucking. I have driven it without the TPS connected and lowered the idle and it drives much better and doesn't throw any codes other than TPS. I don't have any codes thrown and so the question is: should I put the computer into diagnostic test mode? the manual states that-

1 Turn the ignition OFF.
2 Connect terminals TE2 and E1.
3 Drive the vehicle to attempt to simulate fault conditions.
4 If the Check Engine Light (CEL) comes on return to the workshop.
5 Connect TE1 and E1 with your own wire link.
6 Turn ingition ON, the Check Engine Light (CEL) should be flashing.
7 Read codes.

Do I leave the jumper for TE2 to E1 while driving it and then remove and then jump TE1 to E1 to read out the codes? Or do you just jump TE2 and E1, turn the ignition on and then remove the jumper and start the engine?

Any advice is appreciated. My next step is to put it out of it's (my) misery.

(I have read and read and read for days the threads on bucking, surging, etc. So, yes I have full capability of the search function.)

Mako

RJR

Close. After step 4,
a) Do NOT shut off the engine
b) Jumper TE1 to E1 without removing the TE2 jumper.

See this link for a good description of the diagnostic system. http://www.autoshop101.com/forms/h27.pdf
Page 15 (last page) describes the test mode you are talking about.

Makomike

THAT is a handy piece of information to have. Thank you!

RJR

Lots of other good articles on the autoshop101 site.
http://www.autoshop101.com/

Click on the "technical articles" link at the left.