Momentary hesitation after cold start

'97 Sport 4.0 AW4

When I start it up from cold, or it hasn't been running in a good amount of time and has cooled off some, I get a hesitation and sometimes a popping sound when accelerating and a rough idle if i just leave it sit. After it warms up a bit more it never happens again.

I don't know much about sensors and all that stuff, but I'm thinking that they may have something to do with it.

Thanks in advance.

mine has a interesting popping noise aswell after i let off the brake (at a stop sign) and accelerate away

next time ill have to count how many times it pops and feel around for vibs from it

xjh3 said:

'97 Sport 4.0 AW4

When I start it up from cold, or it hasn't been running in a good amount of time and has cooled off some, I get a hesitation and sometimes a popping sound when accelerating and a rough idle if i just leave it sit. After it warms up a bit more it never happens again.

I don't know much about sensors and all that stuff, but I'm thinking that they may have something to do with it.

Thanks in advance.

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My 98 does the exact same thing. I've been chasing this issue down and changed just about every sensor, injector, plug, I even changed the fuel pump and sending unit and it still does it. On mine it only happens every now and then, but after the POP or hesitation, it runs fine and the check engine light comes on with the code PO306, which is mis-fire on cylinder 6, everytime, no other codes.

Hopefully somebody out there has the answer.

my 98 has a small exhaust leak coming out of the headers. when it gets hot it closes up and all whatever noise was comin from it stops. look around your headers for any cracks

Also, when i start it cold, i let it rev up to 1400 or whatever and let it fall, then put it in neutral for a sec, it revs up about 3 seconds after i do that, then drive, and it'll rev up another 3 seconds after wards? Maybe IAC, TPS, MAP?

my 98 has a small exhaust leak coming out of the headers. when it gets hot it closes up and all whatever noise was comin from it stops. look around your headers for any cracks

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I'm not claiming to be an expert, but what does this have to do with it? I just installed a new aftermarket header and it seems that hesitation last longer before regaining normal driveability.