What needs to be done for a 1999 3.4L to go where a 2002 3.4L was because the plugs some of the plugs are different

Asked by Aug 17, 2014 at 09:37 PM about the 2002 Pontiac Grand Am SE

Question type: Maintenance & Repair

some of the plugs are different and do not line up or cannot be plugged in. I am taking the engine from the 1999 and swapping it with the blown 2002 engine though both 3.4L

3 Answers


You will need to swap all of the sensors from your motor to the new motor where the plugs do not match. You will also need to swap the fuel injectors from your motor to the new motor as they are not compatible. The motors themselves did not change between those years.


Check the ECM, I believe they are not the same for those years. It will probably work, but not as well as it could with the correct ECM.


@ Norm the PCM of the '99 is different but is of no concern. The 3400's from both years are pretty much the same engine. As long as the original electrical equipment on the engine is used from the '02 on the older engine it will run normally. In 2000 GM switched between high and low impedance fuel injectors which is why they need to be changed (just remove the upper intake manifold and depressure the fuel rail before starting the swap). (FYI the 3100 was updated around 2000 but even them could be swapped and ran with either PCM with a little more work!) One of the simplest ways to check for sensor/part compatibility is to use an online parts look up database for the two different years of the vehicle. If the same part number is available for both engines, leave it (test it maybe), if they're different, swap it. Temp and pressure sensors are usually good but the TPS, IAC and ICM usually vary. The ICM reads and converts the crank position sensor and controls spark (with a advance/retard signal from the PCM). These vary between years and models of the car based on emissions, power and vehicle (car/mini-van). They can be inter-changed but it is easier/safer to stick with the stock unit that came with the car. Most of the position pick-ups Crank/cam are common units and the reluctor is varied on the shaft it is reading.

Your Answer

Add photo

Related Questions

Grand Am

Looking for a Used Grand Am in your area?

CarGurus has 1,232 nationwide Grand Am listings starting at $1,999.


Search Pontiac Grand Am Questions

Pontiac Grand Am Experts

#1 tenspeed
Reputation 7,610
#2 John Saffrahn
John Saffrahn
Reputation 1,600
#3 Tom Demyan
Tom Demyan
Reputation 1,410
View All

Related Models For Sale

Used Pontiac Grand Prix
27 Great Deals out of 2,864 listings starting at $1,500
Used Pontiac Firebird
7 Great Deals out of 732 listings starting at $3,875
Used Chevrolet Impala
581 Great Deals out of 31,628 listings starting at $799
Used Chevrolet Camaro
205 Great Deals out of 30,804 listings starting at $1,217
Used Ford Mustang
453 Great Deals out of 45,583 listings starting at $1,999
Used Nissan Altima
1,021 Great Deals out of 81,045 listings starting at $1,800
Used Chevrolet Malibu
902 Great Deals out of 79,371 listings starting at $1,500
Used Honda Accord
816 Great Deals out of 85,780 listings starting at $988
Used Toyota Camry
989 Great Deals out of 90,836 listings starting at $700
Used Honda Civic
655 Great Deals out of 90,024 listings starting at $1,299

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.