Lately the cars idle has gone in the crapper and the gas milage is very poor (less than 200 a tank with highway). Whenever you start the car in the mornings you will occasionally get a code that will last for about a minute or two then go off. Also, everytime the car has been sitting for awhile and you start it you can smell gas. I pulled a plug and it is caked with carbon. A couple monthes ago I had the car on a broad band and teh air:fuel was damn near perfect. Also, the car will surge at idle sometimes. Lastly, if thottle is held at 2100-2500 range, but at a constant rpm, while driving, the car seems to have a miss. It jerks a bit.

Suggestions? Maybe bad O2 sensor?

 

Definately need the code your pulling on the PCM. Could be a wide variety of things. Bad coil.... bad opti.... bad o2s... several things but until you know the code you will not know for sure. Take your car to autozone I think they still do the free code pull on the PCM or have someone in your area autotap it for you. Just a suggestion.

 

Thanks for the reply. My autoxray gave out on me unfortunately. I'll have to get the code and post it,.

 

Make sure the EGR valve is not stuck open.

 

No need to take shots in the dark. Get that code and we will be able to tech it out for you.

 

My guess would be a bad plug or wire. If you just installed a set I would say you need to check over them again. Check for blue sparks at night near the plugs. I went through 2 sets of plug wires due to my headers burning them. This all within 2 weeks. Then I bought a custom set of wires, and haven't had a problem since.
My mileage went up 60 per tank after changing both 02 sensors at 80k miles.

On a side note, I wish I got 200 miles per tank....Damn you guys get good mileage, my guess is you don't have a lead foot.

Travis

 

How do I make sure the egr isn't stuck open? I have a plate blocking it at the silver bendy tube thing, so that may not be an isssue. Honestly though, I know jack about this area of the motor.

 

All posts listed above are good things to look for. You would simplify the troublehooting if you found out what code your getting.

You mentioned you blocked off your egr convoluted tube. As suggested above by shoebox (whom always has good suggestions might I add), if your egr is stuck open AND by chance the blocking plate you installed is leaking or has holes in it, it will cause problems as you suggested.

Good luck!

Steve

 

Just got back from autozone. They said they can't scan it since it is obd1 with obd2 connector (95 car). I do have access to datamaster, but I don't know how to pull codes with it.

 

Bad fuel injector?

Crack or leaks in any EGR hoses? Isn't there a way on the 95 to check EGR? Stuff the tailpipe and see a change in idle, or manually play with the EGR diaphram? You should be able to stall the engine. .... Just throwing stuff out there ...

 

I finally gpot it scanned. I am getting a code 43 dtc??? I had this not too long ago and had to change the knock sensor to get the ses lihgt to go away. I never cleared the code, so that could be it, but that wouldn't explain the bad idle. The o2 sensors look good according to the data master. When I say good I mean they are changing values. I haven't looked at the range to see how rich yet. I will play with the egr in the morning.

what does cloging the tail pipes do for me? Why would I want o do that?

 

How many miles on the O2 sensors? I would guess that.

You have changed the plugs and wires right?

 

I don't know about 95's, but some have a backpressure type valve, and restricting SOME of the exhaust flow out of the tailpipe will alllow the engine to run, but create some backpressure and hence affect the idle (if EGR is working).

 

You don't want both of your O2 sensors to read the same, if so something is up. If you have the money and have a lot of miles on them, just change them both. It can't hurt any thing.

 

I have probly about 20,000 miles on these o2's. The plugs are about 1yr old with a couple bottles of nitrous through them, and the wires are brand new. Alittle later in the day I'll hit the plugs and o2's and see if that fixes it. I remember hearing something about autozone o2 sensors. Were they good or bad?