hi Am having trouble with 88 trooper II...it has been backfiring when i back off on the fuel pedal.{ at highway speed}..check engine lite comes on...if i release gas it goes off or if i push on gas it goes off...went to start it yesterday and all lights on dash came on it ran for 30 seconds then died.....went back couple hours later and it started....then again this morning...same thing wont stay running...just had fuel pressure reg changed month ago...now what?????
any help would be great thanks

got to looking at fuses and tapped on the engine relay....heater came on and the dash warning lights went out....ran just fine.pulled the relay out and drove for a bit then it started to die...stalled and needed to be boosted...drove some more till battery was drained again boosted and made it to destination..can some one tell me what this engine relay controls... had people look at it some say fuel,,,some say electric prob????? can i test this relay??? or where do i start...

Sounds like a bad alternator. Is it a 2.6? The fuel pump relay energizes the fuel pump from battery on start-up then the relay flips over to power the pump from the alternator. The reasoning is if you're in a crash and break a fuel line you don't want to keep pumping gas. Could be a bad relay. Switch it out with a matching one to test that theory. Changed your fuel filter?

You might load test the battery too. I know when my alternator went, the battery quit about two weeks later. If the battery is on the low side of good I'd replace both the alternator and battery.

just changed the fuel filter last month...will see if i can get relay tested...if i give it a tap it does cut in so maybe thats all it is...do you know what the engine relay controls?? thanks

Just switch out the relay. I think the one for the headlights is the same thing or buy a new one for $12. Actually do this. Put the key in the ignition and switch it to "on" without cranking the engine. You should be able to hear the relay click and a hum as the in-tank pump comes on. If you're not sure, leave the ignition on and pull the relay out and plug it in again. You'll feel the click when you plug it in.
If you hear the click but no hum from the pump check the wires going back to the pump. Mine corroded off after 10 years of salty highway driving and they'd make and break depending on which way I twisted the wire. If your lucky they might have corroded at the connector so clean it up and reconnect or chop it off and solder/tape/seal the wires straight to each other. Marine Goop makes a good sealer.

Another thing: check the belt tension on your alternator, pull the connectors and clean them up. I still say your alternator/battery sounds like the culprit.

had the alternator rebuilt last week and all seems fine..(170.00 one year warranty parts and labour)thanks to the guy that said dash lights look like a christmas tree...made me really check in to it...now just one more issue of back firing when release gas, and ill almost trust the old beast...thanks to all who posted