UPDATED (see below):

This issue has been around for a month or so for me, but I think I have a better understanding of the symptoms now, which might help find a solution.

It started out with there being a power loss under heavy acceleration. It appeared that the car was shuddering as it strugged to go through second gear around 2500 to 3000 RPMs.

Lately, it's been worse if I drive for a while, shut off the car for a bit and then come back to it.

Yesterday, I could barely make the onramp up to cruising speed.

The interesting thing is that full power seems to come back in higher gears, or at least once I get past 3000 RPMs (she really takes off hard). It's the struggle to get up to speed before that point that's the issue.

I recently replaced the following:

1. Front Brakes
2. Rear CV boots (inner/outer)
3. Drop links (front)
4. Exaust leak off the manifold
5. Balanced all 4 wheels, including swapping out bent rim
6. Alignment
7. Oil Change
8. Spark Plugs (but not wires)
9. Air Filter

Thoughts? Questions?

UPDATE:

The car's symptoms seem to have changed during the process of sorting out the hesitation issues. It went from feel bogged down under acceleration to doing some major bucking with RPMs bouncing all over the place. But only during take-off. Acceleration during highway speeds seem pretty responsive still during cool conditions, and gradually get worse after she heats up.

The new problem that surfacted includes the bucking, but she's also stalled 5 times while stopped at stoplights. She turns right over and starts, however.

Since the first list, the following items have been changed:

1. Plug wires
2. Coil wires
3. O2 Sensor
4. Replaced cats with one with only 38k miles on it (old one rattled)
5. Pinch bolt on TT (unrelated, but the rattle is now gone)
6. Rear brakes (unrealted)

I test drove it with a friend and he's puzzled, as well. He suggested we might start with looking at the fuel pressure regulator. We didn't have the test fitting to check the fuel pressure coming off the rails.

She revs just fine in the driveway. She also looks and sounds great, but she's unfortunately in no condition to drive this way.

Any more suggestions?

 

Vacuum leak somewhere?

 

are your plugs gapped appropriately? ignition wires (arcing) will cause your issue: look at the engine running at night: see any sparks?? small & blue..can't miss them.

IF so, I sell replacement leads for $89 + $8 shipping so you can re-make your ignition wires. If not, check your caps & rotors, I suggest removing, lightly sanding off the carbon to get the shine back to the brass & replace. Or maybe just buy new ones as well, but $200 a set now....used to be $130 a few years back.

 

Swap MAFs

 

tony, can we swap mafs?

 

there were some tiny little blue guys under there. not many, but a few. how many would it take to cause the problem I'm experiencing?

 

Hi, time for a new set of wires try not to drive the car in its present state, misfires wont help the engine, might want to also replace the caps and rotors

 

A beautiful Saturday afternoon, my new plugs were dropped off by the UPS guy. I was ready to fix my problem.

I broke an oil breather hose in the process. After much swearing and a patch job on the hose, I managed to get everything back together without any left over parts.

I hit the road ready to feel my new car. For the first part it was great, no hesitation at all, with the exception of a minor hickup once.

Then I passed 3 other sharks, which was rather nice. Then got on the freeway ... no problems.

15 minutes into my drive I punch it coming off an onramp and the problem resurfaces.

It's not as bad as it was before, but it's still extremely noticable. I replaced the plugs and plug wires, but not the caps. Could that be the remaining issue, or is there something else that is caused by the motor running warm?

 

You do have evidence that you breather and vacuum hoses are all suspect after the break in the breather hose.

 

I'm still experiencing problems. I got new caps and rotors in the mail today to finish up the electrical stuff. I was wondering why it would be worse when the temp is higher or the car is warm?

Is there another issue I'm missing? If it is a vaccum leak, are there suspect areas that i should check first?

The car revs perfectly while stationary.

 

How about your coil wires? Did you replace those? Still sounds like a spark issue to me.. I had a Jag once that behaved the same way - sputtered under load - rev'd fine without load. Turned out the resistors in the plug ends were blown out. Not sure if we have those or not. Also check your grounds. Good luck.

 

Coil wire was replaced. I got the whole set of wires and did everything down the line. I read that the coils either work or don't work, so that wouldn't be an issue. It would just be a matter of passing the signal from the coil all the way down the line, right?

 

Well if they are new, check vacuum and grounds. One other thing to check is the condition of the plugs. Make sure they are not fouled/

 

Caps and rotors replaced tonight.

Guess what?

No change.

 

Plugs... tell me the condition of the new plugs. Pull each one out and take a picture.