1FZE 97 LC power loss _ Please Help (1 Viewer)

[cc72red]

Hi Everyone!
I am in dire need of help. My 1FZE 97 LC has started losing power.
This problem is not consistent as to when it happens. Sometimes after 5 minutes when I first start up in the morning.
Sometimes it will run great first 15 - 20 minutes around 3 miles then starts acting up.

Here's what's going on: If its running ok for the first 3 or so miles, upon a stop sign or slowing down for a light, It will drop idle suddenly to about 400 RPM and shutter and stumble and struggle to keep idle. I give gas and it revs. when I release gas it goes right back down. I usually have to shift to N and put foot on brake while other on gas just to keep it from cutting out. It also refuses to give me anything when accelerating . That's intermittent as well. When she's running good its all working as should. Once it starts this drop in RPM it won't cooperate. Sometimes not wanting to get over 2000 RPMS.. I have to feather and gently go with gas to get it to straighten up.
We just got a bad storm and on way home, Roads were packed with snow. I had no trouble with slipping on road. the trouble i has was inclines. She just didn't want to give me any power to go up the hills she does all the time. Now on a normal day since this started (no snow) she seems to be hesitant to go up those same inclines.
I'm wondering what is causing this loss of power.
I have NO Cats. they have been removed.
I do have an EGR code.
Had an ETC sensor code.. Replaced the sensor
Took to someone to read codes: beside the EGR and the O2 sensor codes i knew about it had misfire on all cylinders . I'm assuming because of this loss of power issue.
We checked the distributor cap.. clean as whistle. Its a fairly new distributor cap ( less than a year ) new spark plugs and wires.
My mechanic is Specialized in these vehicles and owns one. Its just that hes so booked and with another round of snow fall upon us I cant get it to him. I have to drive it because its all i have. I'm just needing some info on possible issues that could be problem to keep it going until i can get it taken care of.
Haven't checked the EGR wiring that I've read to check.
It also is running very rich in fuel. So was thinking it was an air/ gas ratio issue.
Also, Possible vacuum line. I'm also hearing. The problem is. I understand these possible causes but dont actually know what is what to check.
Any advice is greatly Appreciated! Help a Sista out,,
Cindy

 

[ppc]

First thing I would check is the TPS - Throttle Position Sensor.

 

[musthave]

TPS. Check vacuum hoses. Check air duct on intake side.

 

[flintknapper]

TPS. Check vacuum hoses. Check air duct on intake side.

^^^^


This first.

 

[Pascoscout]

Mine did that. Duct cracked between air box and intake manifold. No power and misfire code all cylinders. Crack can be hard to see but if you remove the hose and flex it it will be obvious.

 

[Kernal]

All the above:

Check out this thread, scroll down to Post #39:

Broken air intake hose fix

I have heard that using silicone anwhere near the intake can damage the O2 sensors. Is it true? I also have a broken air intake tube and I am not planning to buy it right now (it costs $200 around here). Can I use a piece of rubber tube (the one used in old-fashioned tires) and gule it around? I...

forum.ih8mud.com

Also look at the two smaller diameter vacuum hoses on top of the valve cover close to the larger rubber air intake hose mentioned above (see photos in thread, click to magnify):

 

[flintknapper]

Mine did that. Duct cracked between air box and intake manifold. No power and misfire code all cylinders. Crack can be hard to see but if you remove the hose and flex it it will be obvious.

Happened to mine as well. Like to never have found the source.

 

[cc72red]

Hi Everyone.
An update... Pulled the TPS to see how it would run while connected to the OBD2 scanner. Ran about 5 miles to the store and back with the sensor out. I ran so good and consistent. The scanner was saying that it was running slightly lean. Could be to the O2 sensor code.
Anyway. PLUGGED THE SAME TPS back in and ran around for about 1.5 hrs today. Making sure I had a couple times where I completely shut off the truck to restart. She ran great the whole time! No stumbles. No power loss. Nothing to indicate that the same issue still existed. So... #fingerscrossed I'm hoping that it was a corrosion/ connection issue with the TPS. If it starts fumbling again, I will buy a new TPS and then go from there.
Thank you so much for all the help!
I will update if anything changes in this issue.

Next on list.... Front wheel bearings. $$$$
Cindy

 

[flintknapper]

Hi Everyone.
An update... Pulled the TPS to see how it would run while connected to the OBD2 scanner. Ran about 5 miles to the store and back with the sensor out. I ran so good and consistent. The scanner was saying that it was running slightly lean. Could be to the O2 sensor code.
Anyway. PLUGGED THE SAME TPS back in and ran around for about 1.5 hrs today. Making sure I had a couple times where I completely shut off the truck to restart. She ran great the whole time! No stumbles. No power loss. Nothing to indicate that the same issue still existed. So... #fingerscrossed I'm hoping that it was a corrosion/ connection issue with the TPS. If it starts fumbling again, I will buy a new TPS and then go from there.
Thank you so much for all the help!
I will update if anything changes in this issue.

Next on list.... Front wheel bearings. $$$$
Cindy

Excellent.......!

 

[cc72red]

UPDATE 2:
After about 2 weeks of driving after reseating Throttle Positioning Sensor the truck started acting up again. So I bought a new one. Put it in and it was worse at first, After a couple more drives it started acting ok again but I still didn't have the power back to right. So, I replaced the upstream O2 sensor since it was coding. I've been driving for 2 weeks now and it's running awesome. When hooked up to OBDII the downstream O2 sensor is holding at 96%. I'm going to put in that new sensor to just to have better readings. As of now, I cleared all codes and for a week now, NO codes have come up. not even the original EGR that it's had for the last year. So, she's running clean right now and code free! I'm so stinking Excited!

 

[flintknapper]

UPDATE 2:
After about 2 weeks of driving after reseating Throttle Positioning Sensor the truck started acting up again. So I bought a new one. Put it in and it was worse at first, After a couple more drives it started acting ok again but I still didn't have the power back to right. So, I replaced the upstream O2 sensor since it was coding. I've been driving for 2 weeks now and it's running awesome. When hooked up to OBDII the downstream O2 sensor is holding at 96%. I'm going to put in that new sensor to just to have better readings. As of now, I cleared all codes and for a week now, NO codes have come up. not even the original EGR that it's had for the last year. So, she's running clean right now and code free! I'm so stinking Excited!

Good work. Sometimes finding ALL of the issues can take awhile. You were vigilant and it payed off for you.

 

[cc72red]

Hi!
So now that I have new TPS, New O2 sensors,.... My LC is having a hard time shifting, It's throwing a PO501 code . Has anyone else thrown this code?
And is there only one VSS sensor near the transmission or is there one in the dash as well ? My speedometer is rock solid... meaning still working accurately according to the OBDII measures when driving. Thanks Everyone!