My 5.7 TPI starts, idles, and performs like new when cold. When it gets warmed up (a couple of miles down the road) and I come to a stop, it will idle extremely low and sometimes stall. It will also start burning oil.

I get it back home and let it set for short time (15 to 30 minutes) and it will idle properly again but will still smoke a little.

Any idea's?

 

Hows about some more info about your car? Make, model, miles on engine, how long you have had the car, when this started to happen, anything else that may be useful?

 

It's an '88 Formula with 107k on the clock but supposedly a couple thousand on the motor. I bought the car last September but it had sat for almost 3 years. I spent the last 8 months doing rust repair, complete re-paint,struts, shocks, brakes, etc. Did not get it on the road till a couple of weeks ago. Running in and out of the garage it ran pretty good but never got a chance to fully warm up. No that I can take it out of the yard, it when the issues started. It would puff a little at startup when cold, but that has stopped.

Have put new plugs, wires, cap, rotor, pvc,fuel filter, all vac lines, and injectors in it (5 out of 8 injectors were leaking). Cleaned the IAC and adjusted the base idle and TPS. Fuel pressure holds steady at 41 at idle and 47 at WOT. No codes set other than the self inflicted codes for disconnecting the timing wire for base timing, disconnecting the MAF, and such from troubleshooting. Tried the propane trick to find any vac. leaks - none. I don't know where to look next.

 

well if you are burning oil there really isnt any sensor or electical problem that will cause that... what oil are you using? what do the plugs look like after burning all this oil? are you sure it is oil and not running rich? have you replaced the ignition module? or tested it hot to see if it was failing?

 

Grobin54, you say 5 of 8 injectors were leaking? That was probably because the o-rings dried out, same thing is possible with your valve seals if they are the umbrella type.

 

Thanks for the reply, the injectors were leaking into the cylinders - soaking the spark plugs. Don't have any history on the engine or valve seals.

 

SpitotR, I am using Valvoline 10W30, the plugs looked fine - burning clean - when it starts smoking the smoke is blue. When it starts smoking it is not heavy like you would use it to fog the yard but it is a concern. Haven't messed with the ign. module yet. When the car is warmed up, other than the rough idle/sometimes stalling the car runs great when you get it off idle and start down the road. Plenty of power. Thanks for your reply.

 

An update on my 5.7 idle and smoking issues. Through the morning I started the engine several times, letting it reach normal temp. each time, hoping the ecm would re-learn the iac, but no change. After a short cool down, I pulled all the plugs and did a compression check again. My results were as follows:

Spark plug #3 showed signs of oil fouling, the rest were fine.

Compression:

#1 165 psi #2 180 psi
#3 170 psi #4 180 psi
#5 170 psi
#7 170 psi

Couldn't get compression hose into #6 or #8 due to headers.

I suspect an intake vacuum leak at the head on the driver side.

Any body have any idea's?