94 Rodeo V6 Check Engine Light On

Hey there,
I have a 94 Rodeo V6,3.2 with 150K miles on. Today when I was driving on the highway going around 70 (rpm is between 2k and 3k I think), I
noticed I start to loosing power and engine started to bucking. Then I found the check engine light is on. Occationally the light would be off and the car seemed to be normal again, but then it would come back and I could felt the enging bucking and losing power. It is especially obvious when I am driving uphill or accelerate. I have to drive below 60 and not sure what happened. I did add gas this morning. I changed oil a couple weeks back and replaced new air filter. Any thoughts? Please help. Thansk!
Cmbaus
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
My guess is that the light comes on because the engine is bucking. The light doesn't appear to be an indication of a computer code. If it were, the light would stay on all the time and never go out until the computer was cleared.
Check the gas cap and make sure it's tight and sealing.
snipped-for-privacy@yahoo.com wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I have had this same problem. It's quite possibly a gas cap issue. When it happens, if you can do it safely, pull over and take a whiff of your exhaust. It will smell very different if your gas cap is not on tight. When it starts bucking, take a look in your side mirror and you might see a lot of dark smoke from the exhaust. When this happens and you crack the gas cap, if you don't get a rush of air from breaking the vacuum, it's a gas cap issue.
-Bill
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The light actually stayed on most of the time. I did stop but I did not check the gas cap. When I started the car again, I noticed the light was off, but I just found the car was sluggish. I did not pay attention to the smoke thing. I was in such a rush that I rented a vehicle and keep going. I will check that on Thursday. Hopefully it is a small matter. Thanks for the input though...
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Sorry to rain on the parade, but a loose gas cap most likely does not cause you engine to all but die.
Don't cheat, buy a Haynes manual, read it, then check for codes. You will have one in memory even with the light off. The computer is hoping you'd get the idea to perform proper maintenance before the year 2100 rolls on by...
Good luck.
snipped-for-privacy@yahoo.com wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I beg to disagree. I have experienced this phenomenon on several occasions. Somebody stole my cap and when I was driving home, the engine ran like crap and would die when I hit a red light. I was getting a lot of dark smoke from the exhaust so I thought perhaps I had bad gas. When I went to refuel, I noticed the cap gone. Replaced it and the problem went away. The issue I am having is that the new cap doesn't always get a good seal and the problem recurs from time to time. The Fix...remove the cap and screw it on again. Works like a champ.

Certainly there could be other things going on here and a proper diagnosis should include checking for trouble codes.
-Bill
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks for all the input. So I came back and got in my car again, which had sit on the parking lot for 4 days. I checked the gas cap and it seemed to be perfect, because when I opened it I heard the sound of pressure release. I tightened it up again anyway.I checked the exhaust pipe and sure it was dirty, lots of fumes and my finger is all black. LOL... Anyway, I drove 110 miles home and the car is smooth and the light did not bother to come on once. A few uphill I was actually hitting 4000 rpm. I am still thinking to pull the code when I have time, so I could know what happened. But I hope myabe it is just becoz bad gas or somehting. I 'll let y'all know.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
1. Have you replaced the fuel filter? or do you know when it was last replaced? I had a situation when I was on 395 in the middle of nowhere and the car seemingly hesitated/bucked/etc. Pulled into an all night auto parts store and replaced the fuel filter. Everything ran fine.
2. I've also read about the oxygen sensor on Isuzu's. Have you replaced it? or do you know when it was last replaced?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I believe I had a new oil filter when I changed oil a couple weeks back. I have not replaced oxygen sensor for a at least 3 years,40 k miles.
Anyway I went to AutoZone today try to have my engine code read. The guy came out and told me he could not read it. He said the adapter is different, and he said AutoZone's reader only has one adapter fits all. Is that true?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Not sure about the reader, but an Isuzu dealer may be able to give you a diagnosis service at a reasonable cost.
But about the fuel filter... it is different than an oil filter. Though, it would not cause your check engine light to come on as I don't believe it is monitored. I guess it is possible that maybe it could come on because of an irregular gas flow causing other issues, thus the light. Replacing it is a simple process that only requires 2 basic clamps on the fuel hose (to prevent gas from spilling) and your hands. If you are not comfortable doing it, any service station can do it.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I've expeirenced this problem with my Rodea as well, but I also notices light traces of oil on the spark plugs too. Not sure if a leaky gasket may or may not have anything to do with this?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.