p1875 poor power/acceleration tach dropping

Hello, I have a 99 Blazer, and here is my story:
One morning, I realized that when I have my RPM on or around 2, it would drop on its own to 1 or so, I would feel like the car is loosing all power and that it might shut off, but then it would get up again and the RPM would rise back, it would do that about three or four times in a row. Now, when I floor the car -especially in the morning- the car doesnt jump up like it used to, but the RPM and the speed would slowly rise up.!!
This does not happen everday. On some blessed days, the car runs just fine. It might be important to mention that the car drives fine on the highways.


I kind of ignored the problem for a couple of weeks until my check engine light went on, I took it to the dealer and here is what they told me:
CODE P1875 RELATED TO DRIVE LINE IN SOME WAY
POSSIBLE SHORT TO GROUND IN VCM OR TCCM

I had no idea what that meant, but they asked me for a bunch of money to change those VCM and TCCM, claiming that the dont even know if that would fix it (why did you charge me for diagnostics then?)

Anyways, They reset the check engine light, and the car was fine for about a week. Then, the check engine light went back on. I took it to a mechanic in my neighbouring gas station. They had it for 2 days!, and then they said : "Well, we were not able to pull any codes out, we checked the transmission fluid for 'metal shavings' but we didnt find any!, we think it is the transmission, but since we're not a transmission shop, we can help you bud" and they slapped me with a $279 bill!

My car is still acting that way. It is not fun to drive anymore! I dont think I should be paying a bunch of money for incompetent mechanics' trial and error troubleshooting.

Can you guys help me? Thanks in advance

I wanted to add that I have had the gas filter changed at Jiffy Lube's. That of course, didnt fix my problem

bump

Just me, but I would get under the truck and clean/inspect your tranny wire harness. It's quick and easy to do - sounds like bad signal/grounds to me. It will make one of these electronic gearboxes act all sorts of stupid. If that does not lick it - get yourself to a reputable tranny shop. Cheaper to get it fixed now, than later when it strands you with blown forward gears and no reverse traction.

Just a thought but have you checked your fuel pressure?

Okay, so today 11/4/2004 the check engine light came on. So I called up a tranny shop here in MN called (Kennedy Transmissions) and took it to them. They called me and said that the code is the same generic P1875.

A couple of hours later. the guys called me and said that they have isolated the problem and it seems that it is in the 4x4 computer (might be the computer chip, a ground in the wires or what not) because when they disconnected the power to it, the truck worked just fine!.

Anyways, they said they would invistigate that some more @ $90 an hours! .. I hate electrical problems .. they're hard to trouble shoot.

I forgot to say that they guys at the tranny shop said that the 4x4 computer makes the truck think it is in low 4X4 (while it is actually in normal 2Hi), so it shifts up to third too fast.

I dont know but this is all cryptic to me.

What this code means is that your PCM is not recieving voltage on a circuit. It should recieve ignition voltage on the circuit unless the vehicle is in 4LO

Hey, I've been having exactly the same problem.
I have gone NUTS trying to find the problem.
I have been an auto tech for 20 yrs and never had such an issue.
But I have been back and forth with another tech on a GM truck forum and this guy knows his stuff.
He should be getting back to me soon.
He is supposed to be hooking me up with some wiring diagrams and such. I'm not crazy about electical, but I'm not gonna pay some schmoe hundreds of dollars to fix a problem that I can do myself. It will just take more time, but it's well worth it.
At first I didn't even realize it was tranny.
I thought it was the motor hesitating, so I changed a bunch of stuff. Most of it was needed, but there were a thing or two I didn't need(fuel pump).Doh !
But we live and learn.
Let me know if you need any info.
Once I get it, I can probably email it to you.

Oh, by the way, my check eng light wasn't on until yesterday, and I have had this going on for almost 3 weeks. The GM tech I have been talking with picked up on the problem right away.

Mike

I am having same problem with my 1999 Blazer LS 4X4. Loss of drivetrain; while accelerating gas it would roll very slow (I feel like I am driving 18 wheel truck with trailer in heavy weight.) but sometime it would accelerating as normal. I noticed RPM jump and drop and forth for a while. The light of check engine did not appear on. I borrowed auto zone diganois device to find a code. it reads manfacurer control transmission P1875. I went to auto zone and gave a code. their computer showed some thing wrong with circuit that caused loss of power. they believe there are loose wire. I checked underneath Blazer and I didn't find any loose wire.
I believe we might need a new tranmission solenoid, what do you think?

I went into other forum and found a list of code. You can check on http://www.z28.com/forum/showthread.php?t=36071. it said 4 WD Low Switch Circuit Malfunction.

hi im new here and have the same problem, could you tell me how to fix this? its causing me pocket aches. changed a bunch of things already: trans fluid and filter, transfercase fluid, engine oil and filter, air cleaner, diff oils, brake pads, fuel filter, cleaned the shift solenoids and valve body, planning to bring down the transmission and transfercase for cleaning too.

i actually have 2 codes u1026 and p1875.

hope you could help.

hi im new here and have the same problem, could you tell me how to fix this? its causing me pocket aches. changed a bunch of things already: trans fluid and filter, transfercase fluid, engine oil and filter, air cleaner, diff oils, brake pads, fuel filter, cleaned the shift solenoids and valve body, planning to bring down the transmission and transfercase for cleaning too.

i actually have 2 codes u1026 and p1875.

hope you could help.
welcome to the site. please create a new thread in the problem diagnosis section as this one is over 3 years old.