Still have an engine hiccup when accelerating. What's my next step?

[CorMun]

'99 Yukon, 56.5k miles

If I floor it at speeds between 55 and 70 mph, I'll get one or two quick stutters when it's accelerating. Overall, the engine seems sluggish. Seems to take forever to get to 60 mph.

So far, I've done the following:

- new rotor, distributor cap, plugs, wires
- I attached a fuel pressure gauge and drove around. PSI seemed to hold steady at 52. Didn't notice any crazy fluctuations except minor increase when accelerating.

There are no issues starting it.

What should my next move be before I take it to a real mechanic? THanks!

 

[swathdiver]

Do you have a scan tool or app on your phone that can see misfires per cylinder? Assuming you can of course!

Have you checked the gap on the plugs and tested the wires for resistance?

 

[Eman85]

Did you change the fuel filter? Was it doing this before you replaced the parts? Check engine light or codes? Any other work done? Access to scan tool to check distributor offset?

 

[CorMun]

Did you change the fuel filter? Was it doing this before you replaced the parts? Check engine light or codes? Any other work done? Access to scan tool to check distributor offset?

No, I haven't changed the fuel filter yet. It's next on my to-do list. And yes, the hiccup was there before I replaced the parts. No engine light and I haven't checked for codes yet.

I'll try to get my hands on a scan tool.

 

[swathdiver]

No, I haven't changed the fuel filter yet. It's next on my to-do list. And yes, the hiccup was there before I replaced the parts. No engine light and I haven't checked for codes yet.

I'll try to get my hands on a scan tool.

At the very least you can buy an OBDII adapter and download an app for your phone. If you have an IPhone, you can download CarScanner in the Apple Store for free and see ALL codes. If you have an Android phone, you can use Torque or Torque Pro and see only engine and transmission related codes. You can also see live data once you get it set up too.

A bi-directional scan tool is better though.

 

[exp500]

'99 Yukon, 56.5k miles

If I floor it at speeds between 55 and 70 mph, I'll get one or two quick stutters when it's accelerating. Overall, the engine seems sluggish. Seems to take forever to get to 60 mph.

So far, I've done the following:

- new rotor, distributor cap, plugs, wires
- I attached a fuel pressure gauge and drove around. PSI seemed to hold steady at 52. Didn't notice any crazy fluctuations except minor increase when accelerating.

There are no issues starting it.

What should my next move be before I take it to a real mechanic? THanks!

Fuel pressure reading was while driving at steady state or at idle in park? Either way it is low. See manual - Free Car Service Manuals from Operation CHARM — No strings attached!

See also post #5 on your previous post and answer as you can. Use a 6 foot hose on fuel pressure gauge. A minimum tool list is fuel pressure gauge, scanner, spark tester, multimeter. About $100 and up for all, and will fix 90 percent of problems relatively easy.