1994 Chevy s10 was starting and idling rough when engine was cold, but when warm ran fine. Now engine will turn over but wont start. Help please.

ALL SENSORS GO BACK TO THE ECM(COMPUTER), THE OXYGEN SENSOR IS EXTREMELY IMPORTANT, TELLS COMPUTER CHANGE OR ADJUST FUEL DELIVERY, AMONG OTHER THINGS, FIX THAT PROBLEM, PROPERLY, THEN U CAN MOVE ON. NEW AIR AND FUEL FILTERS FOR SURE ! IS BATTERY FULLY CHARGED ? THE GAS WE BUY IS GARBAGE, ETHENOL IS KILLING OUR ENGINES, ADD SOME PREMIUM FUEL, NEXT FILLUP, ADD STABIL 360 FUEL STABILIZER TO TANK, ARE YUR SPARK PLUGS AND WIRES IN GOOD CONDITION ? TUNE-UPS DO HELP. FUEL INJECTORS IF THATS WHAT U HAVE, GET DIRTY, CLOGGED, NEED CLEANER ADDED TO TANK, OIL CHANGE ALSO HELPS, GOTTA GET ENGINE RIGHT, AS U WOULD FOR INSPECTION. OR YOU'LL FAIL EMMISSIONS TEST, RIGHT ? GOOD LUCK MY FRIEND

Check the throttle position sensor, or the idle air control valve

check to make sure the catylitic converter is not clogged.

My 1990 S10 pick-up had a similar problem too. It would start up fine (while the engine was cold) then once the engine warmed up it would idle very rough, sputter, and even stall out. My grandpa and I found what was wrong finally. The fuel distributor had been cracked, so when the engine warmed up it would miss (giving either too much or not enough fuel). So I recommend that you check that. Hope this helps.

I had a 96 GMC 1500 with a 5.7 ltr. It would idle rough, especially on start up. After replacing everything under the sun, it turned out the ECM (computer) was shot. I found a used one and plugged it in and it ran fine. I think I paid 50 bucks or so for it. If you know someone with a truck like yours, plug theirs in and see if it fixes it.

Faulty idle air control valve. You could try and clean it with some carb cleaner, or replace it.

does it have a cold start injector seperate from the other injectors usually on the upper intake somewhere with a fuel line going to it

Mine did the same thing at 16K miles, I cleaned the throttle body and the ploblem went away. Took me about 30 minutes.

tps sencor or maf sencor

Could be vacuum leak or bad ignition wire(s).

I had a similar problem on my "93 Ford probe. The engine idled pretty rough with shakes, Turned out to be a head gasket leaking engine coolant into the cylinder during low rpm's. At fast rpm's it was fine becuase the internal cylinder pressure was greater than the hot coolant pressure & would prevent the coolant from leaking in.

A friend has the same problem with his "94 Blazer 4.3 L, throttle body injection, manual tranny. He hasn't fixed it yet, It started a few weeks ago & is getting worse. His gets a fast idle with hiccups which causes the engine shake. He already checked the EGR valve. He also has a severe exhaust problem, Not oilly but very gray & terrible smelly, but only when the fast idle problem happens. THis fast idle hiccup problem starts when the engine is warmed up.