lschafroth Posted March 11, 2012 Report Share Posted March 11, 2012 I have a 2000 Pontiac Grand Prix GTP. I was given this car by my son. He put a cold air intake on it. It is not a oil based filter. The car sputters at WOT. I've read I might need a new performance MAF to fix that. I've read I just need a new tune. I would like some real advice on what I need to do. The car has 158,000 miles. New plug wires, new plugs. New intake manifold gaskets. (son did it in garage at home) I was impressed. Car runs fantastic otherwise. Gets 27-31 mpg on drives with a small tailwind. Very flat here in Iowa. Any suggestions welcome! Lannie Quote Link to comment Share on other sites More sharing options...
Andrew Posted March 11, 2012 Report Share Posted March 11, 2012 first off, welcome. there is zero need for a "performance" MAF until you are over 300hp. You also never need a tune with a CAI. A CAI doesnt change anything other than being less restrictive. I would guess that your fuel pump is getting weak, and not able to supply enough fuel at WOT. Check your fuel pressure at the rail. Andrew Quote Link to comment Share on other sites More sharing options...
lschafroth Posted March 11, 2012 Author Report Share Posted March 11, 2012 first off, welcome. there is zero need for a "performance" MAF until you are over 300hp. You also never need a tune with a CAI. A CAI doesnt change anything other than being less restrictive. I would guess that your fuel pump is getting weak, and not able to supply enough fuel at WOT. Check your fuel pressure at the rail. Andrew I forgot to mention it has a brand new fuel pump in it. A while back I looked at the factory plugs and messed one up so we went and got normal plugs for it. It does not have the better ones rather just the cheap ones that were campatible. Would this be a cause? using cheapo plugs? If so, what plugs would you recommend putting in it? Changing them is pretty easy. Lannie PS thanks for a great forum!!! Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted March 11, 2012 Report Share Posted March 11, 2012 A CAI doesnt change anything other than being less restrictive. obviously, it should also be picking up slightly colder air at least to increase the charge density, but that's implied by it's name. I forgot to mention it has a brand new fuel pump in it. A while back I looked at the factory plugs and messed one up so we went and got normal plugs for it. It does not have the better ones rather just the cheap ones that were campatible. Would this be a cause? using cheapo plugs? If so, what plugs would you recommend putting in it? Changing them is pretty easy. Lannie PS thanks for a great forum!!! what kind of plug? GM DIS systems seem to be very picky about what plugs will work and which ones that will just misfire from day one, even if they work perfectly in another application. i've had autolite platinums do it, dropped down to the equivalent autolite copper, worked perfectly. ACDelco Rapidfires seem to be a very popular choice, i think the 104s? Quote Link to comment Share on other sites More sharing options...
lschafroth Posted March 11, 2012 Author Report Share Posted March 11, 2012 obviously, it should also be picking up slightly colder air at least to increase the charge density, but that's implied by it's name. what kind of plug? GM DIS systems seem to be very picky about what plugs will work and which ones that will just misfire from day one, even if they work perfectly in another application. i've had autolite platinums do it, dropped down to the equivalent autolite copper, worked perfectly. ACDelco Rapidfires seem to be a very popular choice, i think the 104s? I'm not sure what kind is in it. It's been two years and probably 40K since we put them in. it runs great. only sputters when you first romp it. If you floor it while at highway speeds it never cuts out. It only seems to happen when doing from s stop and the tires are spinning or about to spin. It never appears to cut out any other time. gets great mileage. Lannie Quote Link to comment Share on other sites More sharing options...
MonteCarloDude Posted March 11, 2012 Report Share Posted March 11, 2012 GM DIS systems seem to be very picky about what plugs will work and which ones that will just misfire from day one, even if they work perfectly in another application. i've had autolite platinums do it, dropped down to the equivalent autolite copper, worked perfectly. ACDelco Rapidfires seem to be a very popular choice, i think the 104s? This! I have had a set of ACD Rapidfires in my monte for almost 4 years now, they have not gave me one problem yet. Autolite copper's are a great choice as well IMO. Quote Link to comment Share on other sites More sharing options...
Andrew Posted March 11, 2012 Report Share Posted March 11, 2012 are you just experiencing the TCS intervening? did you remove the metal heat shields at the plug wire boots? those can sometimes arc out. Quote Link to comment Share on other sites More sharing options...
lschafroth Posted March 12, 2012 Author Report Share Posted March 12, 2012 are you just experiencing the TCS intervening? did you remove the metal heat shields at the plug wire boots? those can sometimes arc out. I dont know what TCS intervening is. The heat shields are still in place. Lannie Quote Link to comment Share on other sites More sharing options...
slick Posted March 12, 2012 Report Share Posted March 12, 2012 tcs, traction control system. Quote Link to comment Share on other sites More sharing options...
AL Posted March 12, 2012 Report Share Posted March 12, 2012 Take those metal shields off as I have had 2 3800s that were misfiring due to the heat shields... The spark grounds out on them Quote Link to comment Share on other sites More sharing options...
White93z34 Posted March 13, 2012 Report Share Posted March 13, 2012 did anyone remove the MAF screen? Quote Link to comment Share on other sites More sharing options...
GtpKo Posted March 13, 2012 Report Share Posted March 13, 2012 The MAF screen must be in place, it's not restrictive, it smooths out the flow for the MAF sensor. "Cheap" plugs aren't neccesarrily bad. I used copper Autolite 606s, like $2 a piece, had to change them every ~15k miles, but they ran the best on my GTP. When the fuel pump was changed, was the GT or GTP pump put in? The fuel pump for the supercharged engines are different since they need to pump more fuel than the N/A at WOT. If the "regular" fuel pump was put in, then you wouldn't get proper flow at WOT. Turn the traction control on/off and see if it changes things. Also, check the Intake Air Temp sensor placement. It's the small 2-wired sensor before the throttle body. When going to a non-stock intake sometimes the IAT has to be moved and if it's not reading correctly it can throw off the air/fuel ratio. Make sure the MAF is clean, if not reading properly it can cause a studder going from idle to WOT(speaking from experience with my 2000 GTP) And don't get a tune until you have all regular driveability issues out of the way, otherwise you'll have issues on top of issues. Quote Link to comment Share on other sites More sharing options...
virtuetovice Posted March 13, 2012 Report Share Posted March 13, 2012 Weak ICM/coils? Quote Link to comment Share on other sites More sharing options...
9lumina6 Posted March 17, 2012 Report Share Posted March 17, 2012 Kinda funny this came up.....I started having the same exact problem with my 2000 GTP before I put it away for the winter. I was going to try and hunt down the problem when it comes back out. I was going to try replacing the plugs and wires first since they are 3 yrs old. The MAF is the original....so I have a hunch that's what might be making it cut out once in a while. Quote Link to comment Share on other sites More sharing options...
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