I have a 1990 Isuzu Trooper W/2.8L V6,I went to start it the other day and the engine light was blinking,after driving I noticed a loss in power but no missing,I also noticed that when I accelerated 50% pedal or more that the engine light stayed solid on and when I let off it goes back to blinking.after driving about 7 miles I stoped and noticed that my Catalatic converter and both exaust manifolds was RED glowing..so I figured that my Cat was plugged up.I just came back from getting a new Cat and muffler,the manifolds are not getting red like before and it has more exast comming out now...but the engine light is still blinking and still becomes constant when i accelerate,It still has a loss of power sputters when i accelerate but idles good.but now when I let off the throttle going down the road it is backfiring out the tail pipe.please help I cant figure this out and cant spend alot of money figuring it out.Note : from the time it started untill I had the new cat put on I did not put more than 20 miles on it.Oil is fine and so is the coolant and has a newer radiator on it.since i replaced the cat. converter the manifolds seem normal.

Might try posting this over on PlanetIsuzoo. They get a bit more traffic over there now.

Also have you reset your computer (disconnect battery for 20 minutes)after getting the new cats installed? Also if you have an Autozone near you they can read the codes for you and that would help narrow it down.

You need to pull the trouble codes to find out what the problem is. A check engine light, whether flashing or steady, indicates a problem in the emissions control system. The problem could be almost anything.

If you need help pulling or interpreting the trouble codes, post back and I will post the procedure for pulling the trouble codes.

Well some would not repost in this situation but I realize I am human..lol.First off I am a mecanic but I do Industrial machines and have worked on alot of autos but I am old school back when we had points and carberators when they came out with efi's and computers on them I kind of gave up.Any way I was looking up just where this plug was to pull the codes and found out it was in the console between the seats..BAM..a light went off in my head..I was washing my truck last sat in the yard and pulled the cup holder out to clean it..there was a large black plug and beside it was 2 wires both where white w/a blue stripe and yellow rings around them, one of them had a male end and the other had a female end..I figured they was supposed to be connected sooo I connected them I also told myself that the next time I started it if it done anything wrong I would remember this.well I forgot.after this light bulb went off in my head I went out there and disconnected them,man It runs better than it ever did so I must have had a muffler problem all along but it sure runs good now,I know I am a dummy.does anyone know what these 2 wires are for?self diagnosis maybe?

There are two ways to put the computer in Diagnostic Mode, you found one of them! Those (2) wires, as you guessed, should normally be disconnected unless you're checking for trouble codes.

The other way to do it is to short out the (2) pins in the corner of the ALDL plug (likely the large black plug you found).

There's one other set of wires in there that you should be aware of, for the ESC (Electronic Spark Control) disable. Normally connected, this set of wires with an inline quick-disconnect is unplugged when you're checking the engine's base timing.

If you don't unplug these wires you can't read the timing on the scale, due to the way the ESC works.

With the wires unplugged, it acts just like any old Stone-Age points distributor, as far as adjusting timing goes.

Your Troop will run better with a bit more advance, if you're in there checking you might increase advance from the stock setting of 10 deg BTDC to 13 deg.

And you're probably right about the mufflers, if you're no longer glowing red, it was doing so because of restrictions. Likely a plugged cat, real common in the original design.

It should run pretty good with the new exhaust, probably a lot less restriction than the old system, even when it was in good shape.

Here's some good info from this site on things you can do to enhance your 2.8's performance, if you haven't seen already:

http://www.4x4wire.com/tech/60degreeV6/

HTH........ed