srb531

have a 98 w/130k miles, very good mech cond, but lately has a sometimes problem of [ well most of the time] when cold & first started for several minutes has a on & off hesitation when trying to accelarate. if i feather the gas & drive gently i can keep it going ok until it warms up for minute or two then it runs & drives normal.if i dont lightly give it gas & try to accelarate normally it will start to act as if will stall out & ive even had it kinda buck a bit & i'll hear a knocking type of sound which seems to be coming from the drivers side somewhere near the engine compartment. when this happens i have to completely let of the gas for a few seconds & coast then gas it lightly again to keep it going down the road, but after it warms up runs fine. i have no cel on ,i asked a mech. about this & he said w/o a cel on a code to read he really didnt have any ideas ? so here i am . anyone here have a clue for me ? thanks

Radi

Absolutely amazing.


I'd start by cleaning the IAC (and throttle body if it needs it).
Wouldn't hurt to check the TPS for proper operation and check the fuel pressure, but it'd be odd that they only act up for a few minutes when the engine is stone cold. Check anyway though.
Other oddball thing to check- vacuum leak that seals up when the engine warms up. Intake manifold gasket, etc.

rrich

Sounds like the PCM doesn't know it's cold, runs good once warmed up.

Check temp sending unit and IAT sensr.

He's not a mechanic, possibly a parts changer if it's a simple job.

srb531

well today it ran so bad i thought i was going to need a tow home ,but after a pull over & wait a few minutes got it going, then the cel came on so now im gonna get a clue. stopped at advance auto & they read code as front oxygen sensor, bought one installed it & seems to be fine now. i hope thats all it was, cel is still on but it runs good. how long before the cel will go off ? or can i clear it myself ?

Driftunit

Welcome to my world. Mine sometimes when cold takes a crank or 2 then runs rough till she wakes up. It also sputters some just as im getting on the rd but otherwise runs great after shes heated up. Theres a lot of people with this issue ive looked it up myself and havent found any pin points yet. Good luck

RTorrez1

First off change mechanics. If he doesn't know that he can still pull the stored codes he isn't worth a damn. Take it to autozone or any chain parts store and the can check it for any stored codes and we can go from there.

Driftunit

I think you can pull the batt cable for a few mins and itll reset everything. Glad you found your issue though ive replaced my o2 sensor and it helped a little but i still have some morning miss. Im going to try cleaning my sensors next