: 94 STS hesitates or stumbles



landscaperluke
01-16-06, 10:04 PM
My 94 STS has been gradally getting worse over the last several months. At first it was stumbling going up inclines (nothing steep) but now it has been doing it even on flat terrain. On th flats its a slight hesitation, going up hills is really rough (kind of a chugs or jerks). I replaced the fuel filter right away but didnt really do much for the situation. I took off the EGR valve today and cleaned it. It seemed to be "sticky" when pushing the valve open. I don't know if that is normal. I do get a P036 code as a current code (koeo)
Any Ideas?
Thanks in advance...

Ranger
01-16-06, 10:11 PM
The EGR pintle valve should not be sticky at all. That said, I would suspect plugs and/or wires.

landscaperluke
01-16-06, 10:23 PM
Thanks Ranger. I wouldnt be surprised if the plugs and wires were original @ 113,000 miles. Should I try cleaning the EGR till the pintle moves freely. It seems to stick in the closed position and once it gets past the initial "sticky" spot it opens smoothly for the rest of the stroke.

Ranger
01-16-06, 10:58 PM
Yes, defintately free it up. See the Tech Tips section. Then do the plugs and wires but stick with OEM. They're a bit pricey but worth it and will save you problems down the road. http://www.rockauto.com has good prices and very fast shipping.

On a side note I see you are in Crandon. I was just up in Eagle River snowmobiling a week ago. Snow was getting sparse. I assume it is no better?

eldorado1
01-16-06, 11:07 PM
What are the history codes?

landscaperluke
01-16-06, 11:07 PM
OK, sounds good. Ive been wanting to do a tune up anyway. I'll let you know what happens as I go. BTW the snow is still quite thin here, but the forecast is calling for a few inches tonight and tomorrow.

landscaperluke
01-16-06, 11:15 PM
Codes are as follows:
P036
P052
P070
P071
P109
(P036 comes up "current" when engine running)

Ranger
01-16-06, 11:26 PM
P036 (E036) ................................. EGR Valve Pintle Position Out of Range
P052 (E052) .................................................. ..... PCM Memory Reset
P070 (E070) ................................................ Intermittent TPS Signal
P071 (E071) ................................................ Intermittent MAP Signal
P109 (E109) ....... Keep Alive Memory (KAM) Reset/PCM has lost primary battery power

:dance: Snow dance

eldorado1
01-17-06, 01:48 AM
P070 (E070) ................................................ Intermittent TPS Signal
P071 (E071) ................................................ Intermittent MAP Signal


Had another person same thing a while back...

This is indicative of a faulty MAP sensor. I'll try to find the thread.

here: http://cadillacforums.com/forums/showthread.php?t=59075

Sounds like it's just bad enough to *not* set a current code, which is why unlike the guy in the other thread, yours isn't stalling.

landscaperluke
01-17-06, 11:06 AM
Now my question is regarding the MAP sensor possibility, Would the fact that the EGR valve is not fuctioning properly cause the P070 and the P071 codes to be thrown?

eldorado1
01-17-06, 12:15 PM
Now my question is regarding the MAP sensor possibility, Would the fact that the EGR valve is not fuctioning properly cause the P070 and the P071 codes to be thrown?

That's a good question... I guess it's possible. :hmm:

Eldyfig
01-17-06, 04:44 PM
Bad egr will not cause either of those two codes to set.

A misfire is one of the causes for P070 & P071 to set.

Playdrv4me
01-17-06, 06:22 PM
A Faulty throttle position sensor can also cause all kinds of freaky things to happen. You could have a combination of issues there, including the faulty MAP sensor.

landscaperluke
01-17-06, 06:51 PM
Well today I replaced plugs and wires, and cleaned the EGR valve so it moves freely w/o sticking. I took it out for a drive and there is a night and day difference in performance. Very clean acceleration and no hesitation at all. I will know more after the next couple of days as I drive it some more. Ill update if anything changes. Also I had to clean the throttle body since there was a lot of gunk in there. It made it so the throttle could not close properly, so that may have been a contributing factor. Thanks for all the help so far...