98 sohc misfire on start.

[wreckhunter]

My 98 Sohc seems to have developed a bit of a strange problem in the last few weeks, when starting it will fire on what seems to be 3 or 4 cylinders and run like a dog for 10-15 seconds before either clearing and running as normal or cutting out, once started it runs + drives perfectly until you shut it off and try to start again.it doesn't seem to matter if its hot or cold or how long its been standing it always does the same thing. She's fairly well maintained and has had plugs fuel filter ect in the last 6 months and also had all the plenum chamber + lower intake gaskets done about a year back.I'm a bit confused as I can't see it being an ignition problem as it runs 100% once started.Has anybody else had this kind of issue before?

 

[koda2000]

my guess would be intake o-rings. just for goofs, try putting the gas pedal to the floor once before starting the engine (key off). for some reason this seemed to help with my SOHC.

 

[wreckhunter]

I'll try pressing the pedal and see if it has any effect, the intake o rings + gaskets have all been changed not to long ago.

 

[RomeovilleIL]

Do you get any check engine lights when this happens? How's the level of your coolant? What kind of spark plugs were installed (have you pulled any to see what they look like now)?

 

[swshawaii]

IAC link is for OHV, cleaning procedure is similar for SOHC.

http://www.explorerforum.com/forums/showthread.php?t=84220&highlight=clean+iac

 

[wreckhunter]

The check engine lights been permanently on for the last 3 years or so with 1 code for p0171 bank 1 lean, the symptom is a lot like you get in the morning with a head gasket issue but the coolant level never moves + it will miss every time you stop even if you've been on the road for an hour + stop for a miniute and try to restart. I'm wondering about fuel pressure but once it gets going it runs and drives perfectly with no loss of power at all?

 

[wreckhunter]

The spark plugs were NGK's and I've pulled 3 out of one bank and they all look clean and as you'd hope to see them really.

 

[2000StreetRod]

correct the p0171 code

The check engine lights been permanently on for the last 3 years or so with 1 code for p0171 bank 1 lean, the symptom is a lot like you get in the morning with a head gasket issue but the coolant level never moves + it will miss every time you stop even if you've been on the road for an hour + stop for a miniute and try to restart. I'm wondering about fuel pressure but once it gets going it runs and drives perfectly with no loss of power at all?

If the fuel pressure were low it should affect both banks, not just bank 1. I suggest that first you focus on correcting the bank 1 lean condition. Since you've already replaced the upper and lower intake manifold gaskets look for other possible leaks. The following post may help: Intake manifold vacuum lines
Your UK configuration may be different.

 

[wreckhunter]

I was thinking more of the low fuel pressure being the cause of the starting/misfiring problem rather than the lean bank 1,i'll re check the vac lines as shown in the link as it looks identical to the uk set up thanks.