Engine struggling to get power

[brtnstrns]

I've had some idling problems in the past with my car and mostly solved the problem by replacing the IAC. Now, whenever I rev the engine it really struggles to get to RPMs above 1700 or so. It doesn't seem to have much trouble in neutral, but whenever its under load in gear it really struggles getting power to move the car as if the engine is being starved from fuel or air until I get the RPMs above about 1700, then it will start behaving generally normally. But just cruising in any gear around 1500 RPMs it really lugs and shakes and I can feel the car being extremely underpowered. I'm going to replace the fuel filter as it feels as if the engine isn't getting enough fuel but I'm assuming that won't fix the problem entirely. The car has over 105000 miles so I'm not really sure of what to look at. Anyone got any ideas?

 

[N8Dogg98]

fuel filter is a great place to start. Once you replace, let us know if the problem persists.

 

[wmburns]

I get from the OP that the car runs fine above 1700 RPMs. IMO, this is not a fuel filter issue. Why? Because it would not get better at higher fuel flow rates.

Tell us about any mods.

IMO, the first thing should be to look for a vacuum leak. Don't cut corners here. Even a tiny leak can be the source of the problem.

Any exhaust leaks?

Next clean the MAF.

Then check the fuel pressure sensor. Is the fuel pressure sensor vacuum reference line connected and leak free?

Do you have access to an ODB2 scanner capable of monitoring operational data? If so, it would be nice to know the fuel pressure and the Long term fuel trim (LTFT) at idle and load.

This could also be a stuck open EGR valve. Check the vacuum lines to/from the DPFE sensor. Are they leak free?

Apply a hand vacuum pump to the EGR valve and confirm that it opens/closes in response to applied vacuum.

 

[RedDaemon]

can we get a vote for TPS issues?

ive toyed around with this possibility for a similar problem that i have. just wondering if it has A) any plausibility in general B) if it would help this specific situation

 

[brtnstrns]

I should also mention that it seems to run normal after the engine has reached normal operating temperature. It mainly acts up when the engine is first started and the problem probably persists for about 5 to 10 minutes and then it seems to operate normally. I'm about to replace the fuel filter, PCV valve and a corroded vacuum tube (the 90 degree bend going from the driver side valve cover to the air intake). Other than that I will check for other vacuum leaks.

I'm not sure what the EGR valve or DPFE sensor are if you can please clarify what those are and how I would diagnose them.

Thanks!