barlaam1

I have a 94 with a 95 motor 5.0. After driving it for about 15 min it shows a CEL and starts acting real sluggish and shifting hard. I have replaced the ECM, the EGR, The TPS, The MAFS, and O2 sensor all over the corse of the last six months. The ECM was replaced because somehow some water got into it before I owned the truck. Before I replaced it I couldn't get a code off the ECM. Now I Get codes:
121: closed throttle voltage higher or lower than expected
10:
172: HEGO (HO2S) sensor fault / lean
173: HEGO (HO2S) sensor fault / rich

yesterday I checked all the clamps to all the air intake tubes, sprayed the MAFS with Cleaner and cleared all the codes. While driving around town I got 121, 10, and 172. Tonight I'm going to check and clean all my ground wires.

What do you guys think. this is driving me nuts. If I let the truck sit for a couple hours after driving around it is fine. it's only when I drive for a while that it starts throwing these codes. Please help me. I'm tired of throwing parts at this stupid truck.

Just call me Sean

iTrader: (1)

Make sure the TPS is within range.

barlaam1

How do I check to make sure the tps is in range. When I installed it I did the clockwise quarter turn and then screwed it in.

barlaam1

or do I need to check the voltage? and If so How do I do that? I'm kind of dumb when it comes to checking voltage. so please dumb it down for me.

Just call me Sean

iTrader: (1)

The signal wire should be at about .98 volts closed throttle and go up smoothly as you open up the throttle.

barlaam1

Update:
So I cleaned all grounds that I could find. I made sure they were all in contact with bare metal.
Sprayed all the air intake from the MAFS to the Throttle body with carb cleaner, with no change in idle speed.
I re-installed my TPS and checked it it was at like .95 volts I believe.
I took it on a nice long test drive and had the CEL come on after about 15 min.
Came home and tried checking codes like 5 times and it wouldn't read anything wouldn't even make the truck go into test mode.
So I took 10 min re-installed my door handle that I broke off the other day(that's the second one this summer) and then tried checking codes and this is what I got.
111
10
172
In the last six months and probably 3500 miles I have replaced: O2 sensor, EGR, TPS, and MAFS. The distributor cap and Plug wires apear to be pretty new. I've only owned this truck for about 8 months. What should I be spraying with Carb Cleaner and can I hurt anything by spraying too much. This is a 94 with a 95 5.0. the motor supposedly has around 65,000 miles. Total miles on the truck is 162,000. What should I do next? Thanks for the help so far guys and Sean.

Just call me Sean

iTrader: (1)

We do appreciate the extra information that a lot of people don't give, but so you know the '94 and '95 motors are the same so you don't have to keep saying it has a '95 motor. I'm not bitching about it, I just wanted to make sure you knew that.

Make sure the air intake ducting is tight and not leaking. If air gets in after the MAF it will run lean. Make sure the upper intake manifold gasket isn't leaking, some have had problems with that.

ymeski56

Those are the Key on engine off codes?

barlaam1

Yes those are the Key on engine off codes.

Sean thanks for the heads up on the 94-95 thing...I just posted it because I think the 95 truck had more O2 sensors than my 94....at least that's what i've been told. Thanks for the help. Luckly the farthest I have to go in the next few days is just a couple miles.

Just call me Sean

iTrader: (1)

Unless you're in California the '95 has the same number of oxygen sensors as your '94. If it was a California '95 engine with the extra oxygen sensors, swapping it in correctly still makes it the same as a '94.