[Tonifreakshow]

Hello.I'm new(to this forum AND Mustangs). I just recently bought a 1990 GT with 90,000 miles. It starts and idles with no problem. When I'm driving normal speeds in first or second the car surges and bucks. The previous owner assures me it probably needs spark plugs. He stored it every winter and he says hadn't done anything to it this season before I bought it. I bought the plugs but I have a BBK cold air coming in the mail so I'm going to do both at the same time. The thing is that if I start and drive the car cold it doesn't surge, it's only after I restart the car (for instance coming out of a store). Also the volt meter gets low while sitting at a light and goes normal when accelerating.Altenator or voltage regulator? Are they seperate on these cars? Sorry if these are dumb questions but I new to Fords. I've had GMs all my life( mostly Monte Carlo SSs and Firebirds). I DO have mechanical skills and I work on my own stuff but I'd like to know if I'm going in the right direction. The car has the following mods by the previous owner-new T5 with Hust shifter,373 gears,bigger fuel pump and injectors (don't know how bigger),stock headers with dumped Flowmasters(staight pipe-no H),Cobra R hood.I'm looking to upgrade the heads and cam this summer(Patriot aluminum and stage one Trick Flow) I tried to upload pics but I keep getting errors.

[Tonifreakshow]

[ddarkslayer]

start with those sparkplugs then work your way to the fuel filter then the fuel pump. The best way to check the fuel pump and filter is the check the fuel pressure. If somethings wrong work your way back. also check the sticky on reseting the idle. Is your check engine light glowing?

[Tonifreakshow]

No it isn't. The previous owner did mention that he put gas stabalizer in it before winter.

[fogged306]

I would check for codes anyway. Like mentioned already, check your plugs and fuel pressure. Also check the fuel filter. If could be a number of things and it's always a smart move to check stuff that's free first.

[mayosailor27]

salt and pepper connectors at the back of the intake. o2 sensors. check them out and let me know. I have read alot of this even though I have a 95. The foxes have the black and white connections (salt pepper shakers) just check them and see because they have the fuel harness wiring through them. O2's can cause all kinds of crazy shit. make sure they arent broken or have more than 60000/100000 miles on them. burnt wiring for the o2's also causes hell.

[Tonifreakshow]

I had a bad oil leak so I changed the valve cover gaskets.There was a pretty rotten vacume hose under the upper intake. I replaced that and the altenator.I also replaced the spark plugs and it idles better but it didn't fix the problem. I couldn't get the salt and pepper connectors apart . I didn't want to force things because I didn't want to break them. I didn't replace the fuel filter yet but that'll be next. I've been driving it more because the weather is better and I notice the rpms go crazy when it surges. Actually it seems more like a stutter and the car bucks violently.I started thinking it might be an ignition problem.The rotor and cap look good and so do the plug wires and I backed off of the timing but it's still there. The thing is the car has a LOT of power- it get side ways sometimes even when I'm trying to drive normal. Could it be a distibutoer problem? I don't have alot of money to throw parts at it.

[bl_rdrgz]

mine had the same problem clean the MAF. seemed to fix mine. mine also shook bad cleaned that and all is good

[Tonifreakshow]

What did you clean it with? I noticed the last owner had the driverside plug wires and coil wire routed thru the engine hoist bracket on the header so I rerouted them and installed wire separaters and I thought it fixed the problem.I drove it to work this morning and for the first 15 minutes it drove perfectly but then it started again-it was really bad by the time I got off of the freeway.Same coming home.If the MAF cleaning and fuel filter don't work I'm goining to send it to a shop.I thought I was going to pop a head gasket.

[Tonifreakshow]

I cleaned the maf, changed cap,rotor, fuel filter,coil checked the tps and module and timing and still have this problem.Don't know it it's fuel or ignition.Ordered a scanner. Here are a couple of vidio clips.In the first vidio what souds like a sub woofer is the car misfireing or whatevet it's doing.

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[Tonifreakshow]

YouTube - &#x202a;1990 Mustang GT problem&#x202c;&rlm;

[Tonifreakshow]

YouTube - &#x202a;1990 Mustang GT problem part 2&#x202c;&rlm;