95 jimmy - Rough idle, Misfiring, Massive Fuel Consumption

[rpemm]

I have a clean 1995 Jimmy 4X4 6 cyl 4.3L Vortec (W Style engine) with 180,000 miles.

I have added the K&N FilterCharger, Gibson Exhaust, 160 amp alternator with 4 gauge 150 amp fused circuit EFX battery block, Accel high performance Coil/Cap/Rotor, new Plugs, Taylor 8mm Wires, new cam shaft sensor, 2 of 3 New oxygen Sensors (Pre and post Cat), new egr valve, New Fuel Pump and Sending Unit, Fuel Filter, and had an oil change as I always do every 3000 miles (Mobil One Clean) just on engine tune ups.

My truck still has a rough idle with an ozone killing smell, and my check engine light is on. Code says that it is my oxygen sensor #1. This is supposedly in my left exhaust managold according to Chiltons and Haynes but I cannot find it. What ever the problem is, obviously it is running extremely rich since it is causing the truck to drink an entire tank on 120 highway miles and appears that it has the constant hiccups wether at idle or when cruising. Put my foot on the gas and it doesn't hesitate at all.

This also all started when my alternator went out and drove as far as I could to get as close to home as possible before the battery went dead. This started happening right after I replaced the bad 100 amp alternator with a 160 amp alternator. Wether or not it has anything to do with it I don't know but figured that one of you professors might be able to help.

[JackDaniels386]

you need to replace that Sensor, that might be whats causing all ur problems. Sometimes with a bad O2 sensor, it sends the wrong readings to the computer and that makes the computer run your engine too rich or too lean. If you keep driving it around with the engine running rich, your Catalytic converter might go out too.

[BlazerLT]

Originally Posted by rpemm

I have a clean 1995 Jimmy 4X4 6 cyl 4.3L Vortec (W Style engine) with 180,000 miles.

I have added the K&N FilterCharger, Gibson Exhaust, 160 amp alternator with 4 gauge 150 amp fused circuit EFX battery block, Accel high performance Coil/Cap/Rotor, new Plugs, Taylor 8mm Wires, new cam shaft sensor, 2 of 3 New oxygen Sensors (Pre and post Cat), new egr valve, New Fuel Pump and Sending Unit, Fuel Filter, and had an oil change as I always do every 3000 miles (Mobil One Clean) just on engine tune ups.

My truck still has a rough idle with an ozone killing smell, and my check engine light is on. Code says that it is my oxygen sensor #1. This is supposedly in my left exhaust managold according to Chiltons and Haynes but I cannot find it. What ever the problem is, obviously it is running extremely rich since it is causing the truck to drink an entire tank on 120 highway miles and appears that it has the constant hiccups wether at idle or when cruising. Put my foot on the gas and it doesn't hesitate at all.

This also all started when my alternator went out and drove as far as I could to get as close to home as possible before the battery went dead. This started happening right after I replaced the bad 100 amp alternator with a 160 amp alternator. Wether or not it has anything to do with it I don't know but figured that one of you professors might be able to help.

What code are you getting, Bank 1 Sensor 1 rich?

Have you checked you CPI injector yet? Chances are it is shot and you will have to replace it.

Do a search for CPI injector here and in the Blazer forum for more information on what to do.

[rpemm]

Thanks for both of your replies. I read the CPI thread and I really hope that replacing the o2 sensor will do the trick. That is the code that the computer is displaying however I cannot find the o2 sensor in the manafold. Chilton's and Haynes both describes it by saying it's in the left manafold but I am still not finding it. Is there something that I have to remove to get to it without completely removing everything to get a complete visual?

I have an appointment on Wednesday since I don't want to go through the hassle of removing the intake manafold to check the CPI but if it fixes the problem by replacing the o2 sensor before then great!

[BlazerLT]

Originally Posted by rpemm

Thanks for both of your replies. I read the CPI thread and I really hope that replacing the o2 sensor will do the trick. That is the code that the computer is displaying however I cannot find the o2 sensor in the manafold. Chilton's and Haynes both describes it by saying it's in the left manafold but I am still not finding it. Is there something that I have to remove to get to it without completely removing everything to get a complete visual?

I have an appointment on Wednesday since I don't want to go through the hassle of removing the intake manafold to check the CPI but if it fixes the problem by replacing the o2 sensor before then great!

NO!!!

The O2 sensor is probably doing its job and reading a rich exhaust which is causing the code. The CPI is leaking badly.

Would you friggin listen to us!

[chcknugget]

I'm pretty sure your problem is the cpi, but just for your information the sensor is located on the y pipe after the exhaust manifold. You have to go at it from underneath the vehicle.

This seems to be about the time when everyone's 95 cpi's are going out. If you are on your original, that's very impressive! Good luck!

[BlazerLT]

people just don't listen when people give them logical help.

[lehmann]

hard start rough idle bad mpg new fuel pump and filter ,plugs, cap, rotor 6 months ago.I tested fuel pressure turn key on up to 62 falls down immediatly to 0 at idle 54. what to replace next,fuel pressure regulator,or?

[BlazerLT]

Yea, sounds like it is not holding pressure.

[chembrad]

My '94 S15 Vortec V6 ahd 113k miles and had similar symptoms. When I yanked the plenum the CPI was leaking fuel and the EGR and all the intake ports were full of carbon deposits.

I cleaned out all the crud and then pulled the lower intake manifold. There was carbon deposits throughout. So i cleaned all the carbon crud out of the intake ports and then new gaskets and back together.

Runs like a champ now.

Check your EGR valve. If it is full of carbon deposits, then the rest of the intake ports prolly also are all carboned up.