hemihead

My 89 S-10 blazer is having a problem, when starting cold it takes 4-5 seconds for it to fire and when it does it idles sooooo rough. Rev the engine and it takes off and idles at 3000 rpm but comes down to 1800 on fast idle over the next 5-10 seconds. I have replaced the plugs, wires, cap, rotor, fuel filter, air filter, PCV, IAC, TPS, MAP, Temp sender, cleaned the TBI, checked timing, all with no results! After she warms up it starts fine and runs down the HWY fine. Has 65,000 miles and gets about 18 MPG on the HWY. Anybody got a suggestion?

MT-2500

Any codes?
How is fuel pressure?
Got good hot blue spark to all plugs?

__________________
Remember proper testing gives us the answer to many problems.
MT

hemihead

No codes, good fuel pressure, good spark

MT-2500

Like how much fuel pressure.
Good hot blue spark to all plugs?
Double check it the first 3-4 seconds of no start cold.
Watch injectors for good fuel spray.
Pull plus and see if wet or dry on end after 3-4 seconds of no start.

If dry you have a fuel delivery problem.

See if it will fire on a shot of carb cleaner.

Also would help to get a good scanner on it and read out sensor readings.

__________________
Remember proper testing gives us the answer to many problems.
MT