89 dodge power ram 5.9 (long story)

[64barracuda]

I know this is forabodies only but there isn't many people on fto. I just got the pickup above and it doesn't idle worth a damn. It lopes and sometimes backfires and then runs fine and continues the cycle. Anything above idle and it runs fine. Nobody knows what is wrong. Replaced spark plugs, wires, rotor cap, fuel filter, egr, pcv, sti, air filter and rotor. This is where it gets expensive and tired of changing parts, need help. Previous owner said that the problem didn't show up on computer.
Only one injector engages at idle. Someone said that they both should and I should switch them to see but they don't interchange. I've heard of similar problems and each one replaced different parts (from injectors to all sensors and computer) and nothing happed. Does anyone else have this problem?

 

[64barracuda]

If you're curious I paid $800. 90000 original miles. 4wd posi 4sp, reg cab short box. If you need a pull call me.

 

[rmchrgr]

I actually had a similar problem come in to the shop today. Different car ('01 Cherokee) but same idea. Car would stall at idle but when you gave it some throttle, it was fine. Turned out that the idle air control motor was toast. Its a little electric motor bolted to the throttle body that has an inlet/slot for air. It actuates a 'pintle' that meters the amount of air entering the throttle body at idle ('natch). It was all carbon'd up and was stuck. Car started, ran for a few seconds very rough and died unless I gave it a little gas. New plugs were recently installed by another shop, no dice. No codes either. Guy said his check engine light was on but the car was running so poorly that it affected the alternator output. I think it actually may have died because of it and erased the codes - no stored codes, none pending, no 1 trip failures. I put a new IAC in, cleaned up the throttle body and it was good to go.

Not sure how how the idle air is controlled on an '89 TBI engine but it probably has some form of idle air control. In any event, if there is something, it should be easy enough to pop 'it' off the (IAC) and/or your throttle body to see if it needs to be cleaned.

Also might want to check your fuel pump operation. Do you have an in tank or mechanical? Do you have a way to check pressure? You could just disconnect the fuel line and cycle the key just to get a look and see what comes out. (be safe when disconnecting and checking - high pressure gas!) I'd say it's probably not a fuel pump problem since your issue seems to occur at idle. Something might be gummed up.

See here for what you might be looking for. The interweb is your friend.

 

[64barracuda]

I'll try that. I think the pump is in the tank, I wish I could check pressure. Ill try to see what comes out if the IAC isn't it. Thanks alot.

 

[cudamark]

I had a '91 360 TBI Dodge PU that had a similar problem that defied diagnosis and it turned out to be a cracked intake between the exhaust crossover and intake runner. It killed two cylinders at idle like the EGR valve was stuck open or leaking. Above idle it ran fine and actually passed smog! No codes either.

 

[64barracuda]

My dad's pickup did that too. The IAC is working and I havent checked for pressure yet but I think that the injector has something to do with it. I was wrong about them interchanging, it turns out that the caps dont switch sides but I think I will switch the injectors.
I dont think that an electrical problem would cause one not to work so if the same injector doesn't work I will check its connection and test the resistance.