Skip the auto shop - Our mechanics make house calls

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?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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: Car stalled, cannot be started after that. 1997 Geo Metro

Can you hear the fuel pump running when starting the vehicle - when the key is in the ignition "On" position, but before turning the key to "Start"? If not, check for power to the fuel pump, starting with the...

Q: it is not shifting right. like its not engaging or something

Have someone look at the shift linkage on the steering column in the engine compartment when you shift through the gears. It sounds like one of the shift rods may have come off or the shift tube in the column...

Q: My jaguar 97 starts up and shakes and then cuts off after driving for awhile..

Shaking or vibration may be caused by many different things such as faulty spark plugs, poor fuel pressure or misfires. Other things such as a faulty idle air control valve may cause the engine idle to drop below the normal...

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...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...