Why would my engine cruise fine , Idle smoothly while in park but stumble and idle rough while in gear ???? My runner is a 86 turbo RTE

 

Any help Please !

 

Is there a way to check engine/tansmission mounts without engine/transmission removal ???

 

thats what i was going to suggest check your mounts see if any are cracked or bad.... yea you don't have to remove anything to check mounts... theres 2 motor mounts on the side of the motor attacted to the frame just look em up..."search" see if there good. you don't have your idle set to low do you? have you messed with anything?

 

Idle is in correct range and the truck never stalls but seems like it might, and shakes like crazy.

 

my trany mount is very cracked I will have to try and replace, any other suggestions please ?????

 

ChecUV joints too. Take the drive shaft and see if theres play "up and down shake" if soo then ur U-joint needs replacing. How are your leaf springs? Suspension ok? Its turbo auto.... does it seem like ur trans is slipping? Does it go down the road and you stumble and your RPMS go back and forward at the sametime? Is there any checkengine light? Codes? Turbos not acting up is it?

 

well he said that it cuises fine and idles good while in park but idles rough wile in gear...maybe its a vacuum leak, pretty big one if its making the engine stumble around, and im guessing its an auto right? so there should be some vacuum lines for the auto tranny, i think

 

I was originaly thinking it was a vacume leak but I checked things out in that department as best I could. found nothing. new OME suspension. tranny is shifting fine. I still feel it may be a combo of vac leak and bad tranny mount. my mount is very cracked but I dont think it could cause my problem all on its own. I tried using propane to find leaks. Any other suggestions??????

 

Well it may be engine related. I had the same prob along timeago. . It would idle fine and have no issues until a load was put on the motor which would be trans and driving. For me it was the purge canister and PCV valve. I beat on the canister with a hammer a few times to unstick the valve and replace PCV valce for 2 bucks and fixed it. Air filter dirty? Whens the last tune-up you have had? Unless the mount is totally broke and rotten it should not be creating many probs. Hows your PCV system? Fuel leaks? A defective coil can also cause this too. water in gas? fuel pump going out? fuel filter?

 

Guessing you've already done the basic tune-up stuff right: cap, rotor, plugs, wires, coil maybe set the timing and idle appropriately, etc? Checked the throttle position sensor? Compression test?

 

I fixed a vac leak and restored the factory air box, reset the ECU and now I have a much improved idle. not perfect but much better.

 

So I got my truck back from my mechanic today. He checked the compression, new O2 sensor, new AFM, tested ignition system, smoke tested for vac leaks, cleaned/checked idle up valve.

STILL HAVE ROUGH IDLE WHEN IN GEAR ?!?!

 

plugs/wires/cap/rotor?

 

plugs/wires/cap/rotor?

 

plugs/wires/cap/rotor? all checked and or replaced