Q: Engine Running Rough, EGR or TPS?

asked by on

Background info: We swapped in a used (98k) VG33E V6 when the factory VG33E V6 seized at (184k). We just got to the stage of getting it running but we can't seem to get it to run correctly.

My idle is high, about 1,400 RPMS give or take. Idles smooth but when put into gear and with no acceleration is sputters. It accelerates without my foot even on the gas, although not quickly but for example if I get to about 25mph it will continue at that speed for the most part. Not un-operable, but still an issue. It accelerates very slowly. It almost seems like it just doesn't want to go into gear or that the computer doesn't recognize how much I'm trying to accelerate. Even when I put the petal to the floor it takes a second for it to register and even then it only seems like the RPMs raise but the actual acceleration doesn't. So far I have tried to adjust the TPS sensor (has been replaced), the distributor (has been replaced), and the IAC Valve (has been replaced). I have ran codes using an INNOVA 3100 OBD2 scan tool and I was getting an EGR code but that seems to have cleared up and was left with is random misfires. However, the EGR code has just reappeared (P0400) and the random misfires code is gone. I'm not mechanically inclined but I've had my mechanic father (american cars/heavy machinery) help me out and he is even stumped by this. I also wouldn't think that the timing would have to do with these issues other than the backfire noise I get sometimes.

My car has 98000 miles.
My car has an automatic transmission.

Hi there. Swapping out motors today is much more complex than in years past due to the electronics and computer controlled or monitored systems. The issue you’re describing is a common symptom with engine swaps like the one you’ve recently completed; and even professional automotive mechanics are often baffled by the root cause. In some instances it’s related to a connectivity error with the ignition system; either a faulty electrical harness to fuel injectors or the throttle position sensor itself is faulty. It could be as simple as a vacuum leak as well. I wish we could offer more advice, but without being there to inspect the vehicle personally, there really isn’t an easy fix to this solution.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Engine Running Rough, EGR or TPS?

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Transmission shift hard after high speed driving but shifts normal after engine is off for a while.

Hi there. Transmission fluid should be flushed every 50,000 miles to help avoid issues like you are experiencing. So, it's probably a good idea to have your transmission fluid flushed and filter replaced, as the obstruction of debris or worn...

Q: Q: I purchased a new computer for it does it need programed

You would need to have it programmed to your VIN. Have the computer scanned to see if you have a good crank shaft signal first, before replacing the ECM. You may not need the ECM replaced; you may have a...

Q: Q: Shut off

Hello. Are you noticing any other symptoms with the vehicle? There may be several systems that can shut down a vehicle while driving. Even if you are not receiving any diagnostic troubleshooting codes, you should attempt to have the vehicle...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.