4walker

Does anybody know what tune up parts I should try to lower the cold start idle from 2000 back to 1500 on this engine? I replaced the plugs and cleaned the air filter but haven't inspected or r/r ed the cap and rotor or wires b/c I don't know if a pcv or egr valve might be indicated. Any insights?-ps 175,000mi

Elton

ok your saying when you start it in the morning it idles really high ??

r6dallastx

I have the same problem I tuned up everything that I could but it really didn't make much of a difference. I tried disconnecting the cold start injector, and that helped it some the idle when down to 1400 or lower and it didn't stay at a high idle for as long as before. The only thing is that you have to crank the engine a long time in the morning when it's cold for it to turn on. When it's not cold the engine turns on just as fast as before. From what I know it’s the water temp sensor that tells the computer the engine is cold and then sends more gas into the engine. It maybe that water temp sensor maybe going bad and telling the computer it’s too cold and needs more gas when it doesn't. or it may even be the cold start injector that lets to much gas out. I'm not sure

4walker

Yes, when I start it for the first time of the day it will take about 5 or ten minutes to kick down to 1000 rpm or so and when it starts it will be at 2,00 instead of the normal 1500. It also occassionally lill stall after it's been running at highway speeds for an hour or so when I come to a stop, but first it dips down to about 600 or so. I don't know if those are related or not, though.

hondacrusher

theres a good chance your tps is misadjusted, along with your choke. could be a vacuum leak. If it was a sensor, it would most likely pull a check engine light

stevo

Had the same problem pull out you're idle air screw on the throttle body and replace the o-ring. (Do this with eng. already warmed up 15 min. job) It's a common problem on ANY internel cumbustion engine. First step is to get the correct o-ring on, second make sure with eng. off key out that the throttle is just barely resting on the idle set screw then install the air screw with new o-ring make sure to use a little o-ring lube or plumbers grease. Last but not least from bottomed out DO NOT TIGHTEN possition back out 2 turns start engine and then turn idle air screw ither in or out to obtain around 900 base idle engine warmed up to full temp. (NOTE) that screw should go in a little snug this is just the drag caused by the o-ring sealing and doing it's job Good luck

CoedNaked

On really cold mornings my truck will idle as high as 1750 RPM's. Usually it's 1500 though on most mornings though.

AgRunner06

There is on choke on these engines. OBD1 is pretty much useless except for O2 sensors. There can still be a bad sensor and no light.

I would probably start with vacuum leaks.

Cybercook

Thank you Stevo! Ive had a high idle all year and my intake was cracked so I replaced it but I still had high idle at start up when it was cold. I was about to take it to the dealer to solve. I replaced the o-ring on the air screw like you said and its normal again. Thanks for the usefull information. To many ideas and not enough solutions on these posts sometimes!