Possible Injector Problem? Please Help.

[Canadian GTP]

Here's a quick lead up to the problem.

1. 50,000 Mile car, really good shape. Drove it back from otherside of the country (Montreal to Edmonton) and she ran like a charm.

2. Changed Oil, Tranny flush, Air filter and then Spark plugs & wires. It appears after the plug change, is when the problems started.

3. Car idled terrible, almost stalling w/ Bosch Platinum plugs.

4. Pulled out the plugs and put in AC Delco (Stock) and she ran better however this is when i noticed that when the car is running at a constant speed the car jerks quite a bit. Kinda a soft but rapid jerking. Give it a little gas or get off the throttle and all is fine.

5. This happens in every gear, and even if you just let off the break and let the car roll on it's own idle, then it happens aswell. The car also is idling better but by no means really smooth.

I've double checked the plugs and wires and everything is tight, so I don't quite no where to look next?

Any help would be greatful.

Thanks Group!

 

[puddinpower]

does the car have an adjustable fuel pressure regulator? do you have any kind of a scan tool? Sounds like you are lean at cruise that a little more fuel pressure would fix.But you really need to put a scan tool in the car and ck out whats happening.

HTH

Puddin

 

[mikestertwo]

I see you changed the air filter. Are you sure the hose between the mass air flow sensor and the turbo has no leaks?

 

[Canadian GTP]

1. I will be getting a scanmaster 2.1 & AFR very soon. I just got the car 2 weeks ago, and those items are on the priority list.

2. I will look/listen to make sure there's no cracks/leaks, but this condition seemed to occur after the plugs and didn't seem present after the filter change. I will be getting a Big Mouth, LS1 Maf and 3.5 Maf pipe soon aswell.

However, I'd still like to get to the bottom of the problem. I've decided to get some new injectors anyway, as it's nearing that time according to most on the group, I'm leaning towards Bosch 42.5 lb injectors w/ a TurboTweak chip suited to match. I will eventually move to a TA 49 Turbo aswell, as I'm trying to build a mint shape stock appearing Street car, with little if no ambition for the track.

Does anyone have better suggestions for the Injectors?

Thanks Guys!!!!

 

[mikestertwo]

Those injectors should work just fine. I am running Ford 42.5 pound injectors, TA-49 turbo, THDP on a stock long block and running 11.90's@111+mph

 

[TurboDave]

I assume you're double sure the plug wires are going to the correct plugs.
Sorry, had to ask.

 

[Canadian GTP]

I was ridiculously careful when changing the wires, doing 1 at a time, but I will double check tonight against schematics (if i can find some, I've got the CD Manual on the way but it's not here yet).

However, if this was indeed a plug and/or wire issue, would the car run so strong and smooth under throttle? or would a bad wire/plug cause noticeable issues regardless of how much gas I'm giving her.

Thanks again for the support!

 

[tsaltario]

try changing the fuel filter too. If she's too bunged up, could explain the wavering...

 

[Canadian GTP]

Fuel filter was the first thing I changed w/Stock AC Delco. I just double checked the wires aswell, and they are indeed in the correct order.

Thanks again for your suggestions...

 

[corymc]

i had that jerking problem at one time two and changed the maf and that stopped but i then encounter more problems but maf is something you caould try out too.

 

[TurboDave]

Also, check your crank sensor. Make sure it's not loose or moved. If it's loose it will cause a light throttle surge feeling.

 

[Canadian GTP]

I have plans to change the maf to an ls1, so i'll bump that up on the priority list.

TurboDave! Pardon the ignorance but where would i look for the crank sensor, i'll definately check it out. As i mentioned, my manuals are on the way but not here yet.

Thanks!

 

[TurboDave]

The crank sensor is mounted on the front of the block on the driver's side down behind/next to the crank pulley. It senses the rotational position of the crank shaft and signals the ecm.