I recently bough myself a seville 1993 with the 4.9...
Did a tune up (wires,plug, cap, rotor) change the intake gasket and 2 burned injectors with that done I solve most of the problem exept a little hesitation when I accelerate on a complete stop or accelerating on the kick down...

I clean the throttle body and the egr tube and the EGR valve look OK

what can I do more !?!?!?!!?:banghead:

thanks in advance
Bob

Change your fuel filter if you haven't already, check your fuel pressure. Do a search and look for Bbobynski's posts on fuel pressure testing.
PS. check for error codes.

The fuel filter is changed I also did a combustion chamber cleaning with a special device...

OK, do the check on codes and fuel pressure. Pressure a little low might cause the hesitation, there also might be something else out of spec that would show up in an error code.

how du you make that pressure test, you need a special tool ?

Bob

how du you make that pressure test, you need a special tool ?

Bob

Check the codes dude. If you don't know how, I'll provide a link.

To check the fuel pressure, you're going to need a fuel pressure testing gauge. You should be able to find one at the local auto parts store.

Before doing a pressure test, check your fuel pressure regulator (FPR) for leaks. It will be in between the distributor and the throttle body on the bottom side of the fuel rail. There will be a vaccum hose going into the end of it. Take the hose off and see if there is any indication of fuel leakage from the hose end. If there is, that FPR needs replaced.

To do the pressure test (make sure the car has been off a while before doing the following steps):

a.) Locate the Schrader valve on the fuel rail. On the 4.9, it will be located on the front half of the engine under the vanity cover where the plug wires go under. Remove said cover. The valve will be at the end of the fuel rail near the distributor area. It will somewhat resemble a tire air valve.

b.) First, remove the gas tank cap and relieve the air pressure in the tank. Next, remove the end cap on the valve on the fuel rail. Take a screwdriver and puch in the little thingy-ma-hoochie inside the valve. It would be a good idea to have a rag handy as fuel may pour out at an unreasonable rate :bighead: <explosion> This is why you want to have the car off for a while before doing this test.

c.) Once all of the fuel pressure is relieved, take your gauge and connect it to the valve and Make sure it is tight!

d.) Have someone crank the engine while you watch the gauge: fuel pressure should build to about 45 psi (give or take a couple) and hold steady. After that, start the car and let her idle. The pressure rating should drop some (5 or so psi I think). Though it drops, it should be pretty steady and even.

e.) When placing the valve cap back on, make sure the thingy-ma-hoochie inside the valve is not stuck in the valve and make sure the cap is placed on it fairly snug.

f.) Once all of this is done, post the results of your test and we can then figure out what is wrong, if it is so related to fuel pressure or otherwise.

And post the results of your code check!!!

Good luck :cool:

I will do that as soon as the stupid snow will give me a break !!!
Thanks you are the best !!!

Did you check your fuel pressure?

Blaze

are you sure the hesitation is not coming from your tranny, older trannies tend to slip with age.