OXYGEN SENSOR or THROTTLE BODY problem???.....Advice needed

[hokietiger]

Hello,

I have a 1989 Dodge PowerRam W100 (318 c.i./5.2L V8 EFI) with auto trans.....After replacing sparg plugs/wires, PCV valve, air filter, and fuel filter.......issues remain.

At cold startup, she will idle normally for just a few minutes until warmup. Then, after gradual warmup, it sporadically idles down to near stall and sometimes complete stall...At times it will catch itself and return to normal idle for a few seconds then repeat the sluggish drop to near stall.... If you try to immediately restart after complete stall, it's difficult to restart. But, if you wait 10-15 seconds after stalling, it usually restarts easily...I don't think it's the Idle Air control valve as it appears to be working OK.

If I try to drive it, as long as the gas pedal is depressed (like driving down the road), it will do OK. But, when approaching a stop sign, etc. as it drops in rpm, it will usually try to stall out.

Is it an Oxygen Sensor issue??....What about a Throttle Body issue??

Also, where is the Oxygen sensor located and how many are involved??...Sorry, I'm still a novice and don't have a service manual.

I purchased the truck from a guy who bought it new in 1989....It's a good chance that very little has been done to the truck other than basic maintenance...It has approximately 91,000 miles on the odometer.

Any help is GREATLY appreciated!!!

Mike

[DodgeFreak]

one O2 sensor located before the cat....they are in open loop until the engine reaches a certain temp then it goes into closed loop and reads from the O2 sensor. if you have a sluggish O2 sensor it can't compensate fast enough to keep the fuel mixture in check. I had a 92 shadow that the O2 went bad on, no codes, and ran fine cold until I got 3 miles to town and then it would run right die, and it was a 5spd so you had to floor it and slip the clutch, once moving it would run fine. I'm still thinking O2 sensor...

[DodgeFreak]

I've had a couple tbi 318s and work on a few and so has my cousin and we have rarely seen where the tbi caused issues, never had a problem with the injectors or anything.

[hokietiger]

O2 sensor before the cat??....Sorry for being a novice but where exactly is that located??

thanks!!

[DodgeFreak]

Its in the exhaust pipe towards the front. 4 wire square connector.